MPB 43-2 revision 2

Transcription

MPB 43-2 revision 2

THE MINOR PLANET
BULLETIN
BULLETIN OF THE MINOR PLANETS SECTION OF THE
ASSOCIATION OF LUNAR AND PLANETARY OBSERVERS
VOLUME 43, NUMBER 2, A.D. 2016 APRIL-JUNE
ROTATION PERIOD DETERMINATION FOR 833 MONICA
Frederick Pilcher
4438 Organ Mesa Loop
Las Cruces, NM 88011-8403 USA
[email protected]
111.
Periods and Phase Functions from Sparse Photometry." A. J. 150,
Issue 3, article id. 75, 35 pp.
Vladimir Benishek
Belgrade Astronomical Observatory
Volgina 7, 11060 Belgrade 38, SERBIA
(Received: 25 October 2015)
For 833 Monica we find a synodic rotation period of
12.090 ± 0.001 hours and amplitude 0.19 ± 0.02
magnitude.
Previously published rotation periods for 833 Monica are by
Gartrelle (2012), 12.09 hours; and by Waszczak et al. (2015),
12.0823 hours. The first two nights of observations by Pilcher
found a period in close agreement with these values. He asked,
and second author Benishek kindly accepted, an invitation to
collaborate because their observatories being separated by about
120 degrees longitude would enable them to sample different parts
of the lightcurve of this nearly Earth commensurate object within
an interval of a few days. Pilcher at Organ Mesa Observatory used
a 0.35 m f/10 Meade LX200 GPS S-C, SBIG STL-1001E CCD,
unguided, clear filter.
Benishek at Sopot Astronomical
Observatory used a 0.35 m Meade LX200 GPS S-T operating at
f/6.3, SBIG ST-8 XME CCD, unfiltered and unguided.
Photometric measurement, lightcurve analysis, and data sharing
were enabled by MPO Canopus software. New observations on
six nights 2015 Aug. 19 - Oct. 1 provide a good fit to a somewhat
unsymmetric lightcurve phased to 12.090 ± 0.001 hours, amplitude
0.19 ± 0.02 magnitudes. This is consistent with all other published
results. The lightcurve has been drawn with the large number of
data points binned in sets of three with time difference not
exceeding five minutes.
References
Gartrelle, G. M. (2012). "Lightcurve results for eleven asteroids."
Minor Planet Bull. 39, 40-46.
Waszczak, A., Chang, C.-K., Ofek, E.O., Laher, R., Masci, F.,
Levitan, D., Surace, J., Cheng, Y.-C., Ip, W.-H., Kinoshita, D.,
Helou, G., Prince, T.A., Kulkarni, S. (2015). "Asteroid Light
Curves from the Palomar Transient Factory Survey; Rotation
ROTATION PERIOD ANALYSIS FOR
2500 ALASCATTALO
Junda Liu
Suzhou High School of Jiangsu Province
Suzhou, Jiangsu 215007 P.R. CHINA
[email protected]
(Received: 2015 December 18)
Analysis of photometric observations for the minor
planet 2500 Alascattalo shows a synodic rotation period
of P = 2.751 ± 0.002 h with an amplitude A = 0.19 mag.
Main-belt asteroid 2500 Alascattalo was discovered at Heidelberg
on 1926 Apr 2 by K. Reinmuth. Its orbit has a semi-major axis of
2.240 AU, eccentricity of 0.0992, and orbital period of 3.35 years
(JPL, 2015). Previous work found the synodic rotation period
P = 2.754 ± 0.007 h (Behrend, 2013).
CCD photometric observations of 2500 Alascattalo were made at
Lvye Observatory (IAU P34) on 2015 Dec 17 and at iTelescope
Observatory (IAU Q62) on 2015 Dec 12 and 17. The instruments
of Lvye Observatory are a Skywatcher 0.3-m f/5 Newtonian
Minor Planet Bulletin 43 (2016)
Available on line http://www.minorplanet.info/mpbdownloads.html
112
reflector, SBIG ST-402ME CCD camera at –15°C, binned 2x2,
with a clear filter. The image scale is 2.57 arc seconds per pixel.
Exposure times were 60 s. The instruments of iTelescope
Observatory are a Planewave 0.43-m Corrected Dall-Kirkham
telescope and FLI ProLine PL4710 CCD camera at –35°C, binned
2x2, with clear filter. The image scale is 1.83 arc seconds per pixel.
All exposures were 120 s. The raw science images were dark, bias,
and flat corrected using MaxIm DL.
Differential photometry and period analysis were made using MPO
Canopus. A total of 404 data points was used for the analysis. The
lightcurve shows a period P = 2.751 ± 0.002 h with an amplitude A
= 0.19 mag. The period is in agreement with the earlier work.
LIGHTCURVE ANALYSIS FOR
NINE MAIN BELT ASTEROIDS
Giovanni Battista Casalnuovo
Eurac Observatory C62
Bolzano, ITALY
[email protected]
(Received: 2015 December 21
Revised: 2016 January 24)
Photometric observations of nine main-belt asteroids,
1361 Leuschneria, 1511 Dalera, 1536 Pielinen, 2136
Jugta, 2668 Tataria, 5186 Donalu, 10064 Hirosetamotsu,
11268 Spassky, and 14515 Koichisato, were made at the
Eurac Observatory (MPC C62). Results of lightcurve
analysis are presented.
CCD photometric observations of nine main-belt asteroids were
made at the Eurac Observatory (MPC C62). For 1361 Leuschneria,
1511 Dalera, 2136 Jugta, 2668 Tataria, 5186 Donalu, 10064
Hirosetamotsu, 11268 Spassky, and 14515 Koichisato, the
observations were made in late 2014 and early 2015. The
observations for 1536 Pielinen were made in 2011.
All images were obtained with a 0.30-m reflector telescope
reduced to f/4.0, a QHY9 CCD camera, and V filter, and then
calibrated with dark and flat-field frames. The computer clock was
synchronized with an Internet time server before each session.
Differential photometry and period analysis were done using MPO
Canopus version 10.4.3.17 (Warner, 2014) or Peranso version 2.5.
(Vanmunster, 2015).
References
Behrend, R. (2013). Observatoire de Geneve web site.
http://obswww.unige.ch/~behrend/page_cou.html
JPL (2015). Small Body Database Browser.
http://ssd.jpl.nasa.gov/sbdb.cgi
Warner, B.D., Harris, A.W., Pravec, P. (2009). “The asteroid
lightcurve database.” Icarus 202, 134-146. Updated 2015 Dec 7.
http://www.MinorPlanet.info/lightcurvedatabase.html
1361 Leuschernia. This main-belt asteroid was reported as a
lightcurve photometry opportunity for 2015 April on the
MinorPlanet.info web site (http://www.MinorPlanet.info; hereafter
referenced as MPI). The derived synodic period was P = 9.646 ±
0.001 h with an amplitude of A = 0.19 ± 0.08 mag. Clark (2016)
reported a period of 12.0893 h with A = 0.75 mag using data
obtained about one month after the observations reported here.
Given the scatter in the data, the solution here is not a strong one.
The lightcurve is shown mostly for a guide for future observations.
Warner, B.D. (2013). MPO Software, MPO Canopus version
10.4.3.17. Bdw Publishing. http://minorplanetobserver.com/
1511 Dalera is a main-belt asteroid that was reported as a
lightcurve photometry opportunity for 2015 February (MPI). The
derived synodic period was P = 3.881 ± 0.001 h with an amplitude
113
of A = 0.14 ± 0.05 mag. Salvaggio et al. (2015) and Scardella et al.
(2015) both reported a period of 3.880 h.
A mean of 25 values was used to find V-R = 0.35 ± 0.05 mag. This
value is typical of C-type asteroid (Shevchenko and Lupishko,
1998). Assuming C-type, the geometric albedo is
pv = 0.06 ± 0.02 (Shevchenko and Lupishko, 1998).
This assumed albedos reported in this paper based on Shevchenko
and Lupishko should not be taken as fact since some very different
taxonomic types have similar V-R values. A better estimate would
use at least two color indexes. Thermal observations combined
visual data are used to determine the actual albedo. In this
particular case, the estimate is confirmed by the results of Masiero
et al. (2012), who found pv = 0.066 ± 0.009.
Pravec et al. (2011) reported 1536 Pielinen to be a tumbler with
periods of 66.22 h and 52.05 h. Behrend (2011) reported a period
of 67.43 h, but without signs of tumbling.
2136 Jugta. The main-belt asteroid 2136 Jugta was reported as a
lightcurve photometry opportunity for 2015 February (MPI). The
name commemorates Dr. J. U. Gunter (1911-1994) who published
a precursor to the Minor Planet Bulletin entitled Tonight’s
Asteroids. The name “Jugta” is a combination of Gunter’s initials
and his publication. For his promotion of the field, Gunter
received the 1983 Amateur Achievement Award of the
Astronomical Society of the Pacific and in 1989 the Caroline
Herschel Award of the Western Amateur Astronomer Society. The
derived synodic period derived for 2136 Jugta was P = 6.457 ±
0.001 h with an amplitude of A = 0.37 ± 0.09 mag. There were no
previous results for Jugta found in the LCDB (Warner et al., 2009).
1536 Pielinen. The main-belt asteroid 1536 Pielinen was reported
as a lightcurve photometry opportunity for 2011 October. It’s a
slowly rotating asteroid with the derived synodic period being
P = 66.1 ± 0.1 h with an amplitude of A = 0.75 ± 0.12 mag. A
secondary period of 6.43 ± 0.01 h was also found, but it may be a
harmonic of the main period.
2668 Tataria was reported as a lightcurve photometry opportunity
for 2015 October (MPI). The derived synodic period was P = 2.78
± 0.01 h with an amplitude of A = 0.20 ± 0.08 mag.
114
5186 Donalu. The derived synodic period was P = 3.15 ± 0.01 h
with an amplitude of A = 0.25 ± 0.07 mag. The V-R color index is
0.39 ± 0.05 mag (mean of 10 values). This is typical of C-type
asteroid (Shevchenko and Lupishko, 1998). Assuming C-type, the
geometric albedo is pv = 0.06 ± 0.02 (Shevchenko and Lupishko,
1998).
11268 Spassky. The main-belt asteroid 11268 Spassky was
reported as a lightcurve photometry opportunity for 2015
November (MPI). The derived synodic period was P = 5.646 ±
0.001 h with an amplitude of A = 0.43 ± 0.08 mag. Hayes-Gehrke
et al. (2016) report a period of 5.645 h, making the two results in
very close agreement.
10064 Hirosetamotsu was reported as a lightcurve photometry
opportunity for 2015 November (MPI). The derived synodic period
is P = 8.054 ± 0.001 h with an amplitude of A = 0.56 ± 0.09 mag.
The V-R color index is 0.41 ± 0.05 mag (mean of 20 values). This
value is typical of an M-type asteroid (Shevchenko and Lupishko,
1998). Assuming M-type, the geometric albedo is
pv = 0.17 ± 0.04 (Shevchenko and Lupishko, 1998).
The color index of V-R = 0.35 ± 0.05 mag (mean of 29 values) is
typical of C-type asteroid (Shevchenko and Lupishko, 1998).
Assuming C-type, the geometric albedo is pv = 0.06 ± 0.02
(Shevchenko and Lupishko, 1998).
Hanus et al. (2015) reported a sidereal period of 12.1277 h based
on a lightcurve inversion model. A synodic period of 8.052 h was
found by Behrend (2015), which is in close agreement with the
result given here. The two shorter periods are 2/3 of the long
period. This could indicate a miscount of rotations over the time
span of the data set when using the longer period. This is
sometimes called a rotational alias.
14515 Koichisato. The main-belt asteroid 14515 was reported as a
lightcurve photometry opportunity for 2014 December (MPI). The
derived synodic period was P = 4.265 ± 0.001 h with an amplitude
of A = 0.51 ± 0.10 mag. There were no entries in the LCDB
(Warner et al., 2009) for this asteroid. A color index of V-R = 0.42
± 0.07 mag was found from the mean of 20 values.
The absolute magnitude (H) and slope parameter (G) were found
using the H-G calculator function of MPO Canopus. Ten values
were obtained using the maximum values of the lightcurve that
spanned a phase angle range of 1-14°. This led to H = 11.172 ±
0.071 mag and G = 0.525 ± 0.159.
The value for G would indicate that the asteroid has a high albedo,
pv > ~0.45 (Warner et al., 2009). According to Shevchenko and
Lupishko (1998), the color index indicates a medium albedo M-
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type asteroid, 0.17 ± 0.04. Based on data in the LCDB (Warner et
al., 2009), the M-type asteroids have an average G of 0.20 ± 0.07.
The measured value of G seems to conflict with the estimated G
and pv based on a one-dimensional color index. This case may
caution against assuming values based on limited data.
Pravec, P., Wolf, M., Sarounova, L. (2011).
http://www.asu.cas.cz/~ppravec/neo.htm
Salvaggio F., Marchini A., Franco L. (2015). “Rotation Period
Determination for 1511 Dalera and 2271 Kiso.” Minor Planet Bull.
42, 226.
Scardella M., Franceschini, F., Tomassini, A. (2015). “Rotational
Period of 1511 Dalera” Minor Planet Bull. 42, 216.
Shevchenko V.G. Lupishko D.F. (1998). “Optical properties of
Asteroids from Photometric Data.” Solar System Research 32, 220232.
Vanmunster, T. (2015). Peranso software v 2.5.
http://www.peranso.com/
Warner, B.D., Harris, A.W., Pravec, P. (2009). “The Asteroid
Lightcurve Database.” Icarus 202, 134-146. Updated 2015 Dec 7.
http://www.minorplanet.info/lightcurvedatabase.html
NEA 2015 VY105: A NEW TUMBLING ASTEROID
Albino Carbognani
Astronomical Observatory of the
Aosta Valley Autonomous Region (OAVdA)
Lignan 39, 11020 Nus (Aosta), ITALY
[email protected]
Luca Buzzi
G.V.Schiaparelli Astronomical Observatory
Varese, ITALY
We present the results of photometric observations on
near-Earth asteroid (NEA) 2015 VY105. Lightcurve
analysis shows that it is a tumbling asteroid with synodic
rotation periods P1 = 0.0386 ± 0.0001 h with amplitude
A1 = 0.96 mag and P2 = 0.061 ± 0.001 h with amplitude
A2 = 0.57 mag. After 2008 TC3, this NEA is the fastest
and smallest tumbling asteroid.
Acknowledgments
I would like to thank Lorenzo Franco, Balzaretto Observatory
(A81), Rome, Italy, for data processing asteroid 1536 Pielinen.
References
Clark, M. (2016). “Asteroid Photometry from the Preston Gott
Observatory.” Minor Planet Bull. 43, 2-5.
Hanus, J., Durech, J., Oszkiewicz, D.A., Behrend, R.,
Carry, B., Delbo, M., Adam, O., Afonina, V., Anquentin, R.,
Antonini, P., and 159 coauthors. (2015). arXiv:1510.07422.
Hayes-Gehrke, M.N., Bring, R., Brody, D.D., Deychakiwsky, D.,
Huang, R., Leitess, S., Mandapat, J.C., Shcroeder, C. (2016).
“LightCurve Analysis and Rotation Period Determination for
Asteroid 11268 Spassky.” Minor Planet Bull. 43, 142.
Masiero, J.R., Mainzer, A.K., Grav, T., Bauer, J.M., Cutri, R.M.,
Nugent, C., Cabrera. (2012). “Preliminary Analysis of
WISE/NEOWISE 3-Band Cryogenic and Post-Cryogenic
Observations of Main Belt Asteroids.” Ap. J. Letters 759, L8.
Near-Earth asteroid 2015 VY105 was first observed at Catalina
Sky Survey on 2015 Nov 14 and passed very close to the Earth’s
surface (34,000 km) just 19 hours after first being detected. The
asteroid was followed worldwide until 2015 Nov 15. From the
orbital parameters taken from JPL Small-Body Database Browser1
(a = 2.2077 AU, e = 0.65532, q = 0.76096 AU), it appears that
2015 VY105 belongs to the Apollo class of near-Earth asteroids.
Based on its absolute magnitude, H ~ 29.0, we can assume a
diameter ranging from 3 to 9 meters, depending on its assumed
albedo. An object of this type can also be considered a big
meteoroid.
Here we present a lightcurve obtained from the astrometric images
taken from Nov.14.89792 to 14.90555, (i.e., covering about 11
minutes) at G.V. Schiaparelli Astronomical Observatory and
1
http://ssd.jpl.nasa.gov/sbdb.cgi#top
116
analyzed in OAVdA. About 119 unfiltered images of 2-second
exposure were obtained with the 0.60-m f/4.64 reflector and CCD
SBIG ST10-XME (2184×1672 pixels, 6.8 microns) that was
binned 3x3. The combination gave a field-of-view of 18.4×12.3
arcminutes and a pixel scale of 1.51 arcsec/pixel.
At the time of the observations, 2015 VY105 was 0.0021 AU from
the Earth and 0.991 AU from the Sun at a phase angle of 25.7°.
The sky motion averaged about 90 arcsec/minute in PA 265.8°.
The asteroid was in the constellation Cetus at an airmass of 1.62.
Lightcurve and Periods
One of us (AC) used MPO Canopus (Warner, 2009) version
10.7.0.6 for the differential photometry on astrometric images and
for the period analysis of the lightcurve. For the photometric
reduction, all 119 images were included. An elliptical annulus was
used to measure the target, with the major axis parallel to the
asteroid’s motion. The raw lightcurve (Fig. 1) show a complex
non-repeatable oscillation with an amplitude of about 1.6 mag.
The results of the initial Fourier analysis are shown in Figs. 2 and
3. The data points were binned in groups of two in order to reduce
random fluctuations. There is a dominant solution with a period of
about 0.04 h (~2.4 minutes) assuming a bimodal lightcurve.
However, the fit is not very good, there being some data points
well away from the model curve. In fact, the period spectrum also
showed the presence of two broad minimums near 0.03 and 0.06
hours. This fact and the complex non-repeatable raw lightcurve of
Fig. 1 made us suspect that there might be two periods that overlap
each other and that the asteroid might be tumbling.
Using the asteroid lightcurve database (LCDB; Warner et al.,
2009; 2015 Oct 10 release)2 and limiting the search to tumbling
asteroids with a diameter in the range 0-100 m, we found only 15
asteroids in this size range and that 2015 VY105 is the second
fastest and smallest tumbling asteroid, the fastest being 2008 TC3,
which entered Earth’s atmosphere on 2008 Oct 7 (Jenniskens,
2009).
The rotation period of this asteroid is below the cohesionless spinbarrier value of about 2.2 h. This is consistent with its small size of
well under 0.15 km (Pravec and Harris, 2000). The period and size
put constraints on the internal structure of the asteroid, i.e. it’s a
strength-bound body and not a so-called rubble pile.
The tumbling state is not permanent; the damping time back to
single axis rotation is given by Paolicchi et al. (2002) as
τ ≈ (1/17)3P3/D2
(1)
where τ is given in billions of years, P is the rotation period in
hours, and D is the diameter in kilometers. Using P = 0.04 h and
D = 0.006 km, we estimate that 2015 VY105 could be a fragment
of a collision that occurred about 0.3-0.4 million years ago.
The Tumbling Spin State
Excluding external thermal forces such as the YORP (Yarkovsky–
O'Keefe–Radzievskii–Paddack effect (Rubincam, 2000), most
asteroids rotate at a constant rate around a direction fixed in space
(pure spin state). This condition requires that the angular
momentum vector L and the angular velocity vector ω are parallel
along one of the three principal inertial axes (PIAs) of the body.
However, for some asteroids in a most general rotation state, L and
ω are not parallel with one another or with the body’s PIAs
(Paolicchi et al., 2002). This condition is described as nonprincipal axis rotation (NPAR) and asteroids which are in this state
are called tumbling asteroids. The tumbling state may be the
consequence of a collisional event between asteroids, a flyby of a
planet, or radiation forces such as YORP. A famous example of a
tumbling asteroid is 99942 Apophis (Pravec et al., 2014). The
interesting thing is that tumbling asteroids show two frequencies in
the lightcurve (Pravec et al., 2005).
Using the dual-period search tool implemented in MPO Canopus,
we found two independent periods for 2015 VY105. The results
are shown in Figs. 4 through 7. The synodic rotation periods are P1
= 0.0386 ± 0.0001 h with amplitude A1 = 0.96 mag and
P2 = 0.061 ± 0.001 h with amplitude A2 = 0.57 mag. We asked Petr
Pravec (Ondřejov Observatory, Czech Republic) to make an
independent analysis from the same data. His results confirmed the
tumbling nature of the asteroid with rotation periods
P1 = 0.0384 ± 0.0001 h and P2 = 0.059 ± 0.002 h, values virtually
identical to ours (Petr Pravec, personal communication).
Figure 1. The raw lightcurve of 2015 VY105 with all 119 photometric
points.
Figure 2. The phased lightcurve of 2015 VY105 with the data points
binned in groups of two.
2
http://www.minorplanet.info/PHP/lcdbsummaryquery.php
117
nd
Figure 3. Period spectrum for 2015 VY105 (2 order fit). The
dominant solution near 0.04 h is for a bimodal shape. The minimum
near 0.02 h represents a monomodal lightcurve. The two minima
near 0.03 h and 0.06 h led to speculation about an additional period.
Figure 4. The phased lightcurve of 2015 VY105 with the period P1
only (data points binned in groups of two).
Figure 6. The phased lightcurve of 2015 VY105 with the period P2
only (data points binned in groups of two).
Figure 7. Period spectrum for the secondary period P2. The
minimum near 0.06 h represents a bimodal solution. The minimum
near 0.03 h corresponds to a monomodal solution.
Acknowledgements
The authors thank Petr Pravec for the check of the results of this
interesting asteroid. This research has made use of the NASA’s
Astrophysics Data System and JPL’s Small-Body Database
Browser. Research at the Astronomical Observatory of the Aosta
Valley Autonomous Region was supported by a 2013 Shoemaker
NEO Grant. Work at the G.V. Schiaparelli Astronomical
Observatory was supported by a 2015 Shoemaker NEO Grant.
References
Jenniskens, P., Petrus, M.M., Shaddad, M.H., Numan, D., Judoda,
A.M., Almahata Sitta Consortium. (2009). “The Impact and
Recovery of 2008 TC3.” Nature, 458, 485-488.
Figure 5. Period spectrum for the period P1. The bimodal solution is
at about 0.04 h and the monomodal solution is near 0.02 h.
Paolicchi, P., Burns, J.A., Weidenschilling, S.J. (2002). “Side
Effects of collisions: Spin Rate Changes, Tumbling Rotation
States, and Binary Asteroids.” In Asteroids III (W. F. Bottke, A.
Cellino, P. Paolicchi, R.P. Binzel, eds.) pp 517-526. Univ. Arizona
Press, Tucson.
Pravec, P., Harris, A.W. (2000). “Fast and slow rotation of
asteroids.” Icarus, 148, 12-20.
118
Pravec, P., Harris, A.W., Scheirich, P., Kušnirák, P., Šarounová,
L., Hergenrother, C.W., Mottola, S., Hicks, M.D., Masi, G.,
Krugly, Yu.N., Shevchenko, V.G., Nolan, M.C., Howell, E.S.,
Kaasalainen, M., Galád, A., Brown, P., Degraff, D.R., Lambert, J.
V., Cooney, W.R., Foglia, S. (2005). “Tumbling asteroids.” Icarus
173, 108-131.
Pravec, P., Scheirich, P., Durech, J., Pollock, J., Kusnirak, P.,
Hornoch, K., Galad, A., Vokrouhlicky, D., Harris, A.W., Jehin, E.,
Manfroid, J., Opitom, C., Gillon, M., Colas, F., Oey, J., Vrastil, J.,
Reichart, D., Ivarsen, K., Haislip, J., LaCluyze, A. (2014). “The
tumbling state of (99942) Apophis.” Icarus 233, 48-60.
Rubincam, D.P. (2000). “Relative Spin-up and Spin-down of Small
Asteroids.” Icarus 148, 2-11.
Warner, B.D. (2009). MPO Canopus software. Bdw Publishing,
http://minorplanetobserver.com/
Figure 1. Period spectrum over a range of 2.2 – 26.0 h.
Lightcurve Database.” Icarus 202, 134-146. Updated 2015 Dec.
LIGHTCURVE ANALYSIS FOR 2343 SIDING SPRING
Melissa N. Hayes-Gehrke, Scott Lanoue, Phillip Waugh,
Brannon Hanks, Leron Gil, Joshua Gehres, Christina Zendman,
Emily Harman, Charles Tran-Dac
Department of Astronomy, University of Maryland
College Park, MD 20742 USA
[email protected]
(Received: 2015 December 21
Figure 2. Phased lightcurve with a rotation period of 3.3609 ± 0.0007
h.
Rev: 2016 January 22)
Photometric observations over the course of three nights
in 2015 October and November were collected for
asteroid 2343 Siding Spring. The asteroid is most likely a
fast rotator. For our data set, we find a rotation period of
2.405 ± 0.0003 h provides a reasonable fit.
The main-belt asteroid 2343 Siding Spring was discovered at the
Siding Spring Observatory on 1979 June 25 by E.F. Helin and S.J.
Bus. Our observations of the asteroid took place on 2015 October
16 and 22 and November 30.
A total of 36 images were used in creating the lightcurve. They
were taken using the iTelescope 0.43-m T7 telescope in Nerpio,
Spain, with an SBIG STL-1100M camera. The anti-blooming gate
(ABG) CCD chip has an array of 4008x2672 9-µm2 pixels. Full
well depth is 5000 e–. The exposure time was between 240-300
seconds and a luminance filter was used. The data were processed
in MPO Canopus (Warner, 2013) using Fourier analysis, which
found a rotation period of 2.4050 ± 0.0003 h.
The period spectrum (Figure 1) shows a clearly defined minimum
at 3.3609 h. Figure 2 is the phased lightcurve representing this
result. Looking at the lightcurve, we can see some peculiarities. It
has three maxima, which is not implausible, but is uncommon. The
maxima and minima vary in a way that does not seem typical for
asteroid lightcurves. There is also a section of this phased
lightcurve that lacks data points, which is likely why this fitted
period had the lowest RMS value. The unusual number of maxima,
along with the gap in the data for this period, makes it unlikely that
this rotation period is correct.
Figure 3: Period spectrum plot for a range of 2.2 – 2.9 h.
Because the rotation period corresponding to the lowest RMS from
the Fourier analysis did not seem to lead to a reasonable lightcurve,
we tested rotation periods in the range of 2.2-2.9 hours. The period
spectrum in Figure 3 shows no clearly-defined minimum for us to
choose one specific solution. By phasing the data to numerous
rotation periods in this range, we selected the rotation period of
2.2405 ± 0.0003 h as the one that appears most acceptable. Since
we have a limited number of data points, we suggest that more
observations of this asteroid be made to confirm this result.
119
PHOTOMETRIC ANALYSIS OF 3000 LEONARDO
Melissa N. Hayes-Gehrke, Bryant Ceballos, Stephen Kind, Jeremy
Choi, Patrick Sison, Michael Marbukh, Joseph Wu,
Joseph Sciamanna, Timothy Riley, Yuval Cydulkin, Ryan Mullen,
Daniel Gallagher, Nitay Ravin, Margarita Nudel-Linetsky,
Al-Latif Alston, Austin Ortel
[email protected]
Figure 4. Phased lightcurve with a rotation period of 2.2405 ± 0.0003
h.
We researched 2343 Siding Spring in the asteroid lightcurve
database (LCDB; Warner et al., 2009) and found that there were
no previous reports of a rotation period or lightcurve for this
asteroid. The NASA/JPL Small-Body Database states that 2343
Siding Spring has an absolute magnitude of 13.3, indicating that
this asteroid has a diameter on the order of 10 km. With a rotation
period of 2.2405 ± 0.0003 h, the asteroid is rotating very quickly
for its size. Pravec and Harris (1999) demonstrate that some
asteroids of this size have been reported to spin at a rate of up to 11
full rotations per day, indicating that our result is unusual, but
plausible.
After the initial submission of our paper, our reviewer brought to
our attention the CBET by Pollock et al. (2015) announcing the
discovery that 2343 Siding Spring is a binary system, with an
orbital period of 11.789 ± 0.003 h and a primary rotation period of
2.10637 ± 0.00008 h. In light of this new result, it seems clear that
our lightcurve was based on brightness changes due to the
primary’s rotation.
Acknowledgements
Observations of main-belt asteroid 3000 Leonardo were
made in Mayhill, New Mexico, on 2015 Oct 24 and Nov
1-2. Analysis of the data indicated a rotation period of
7.524 ± 0.021 h.
CCD photometric observations of main-belt asteroid 3000
Leonardo were made at Mayhill, New Mexico (North 32° 54’,
West 105° 31’, elevation 2,225 meters) using a 0.43-m telescope
with 0.66 focal reducer resulting in a focal length of 1.94 m. The
camera was a front-illuminated FLI-PL6303E CCD with
3072x2048 pixels operating at –35ºC. All exposures were 300 s
using a luminance filter.
Our photometric and lightcurve analysis were conducted using
MPO Canopus (Warner, 2015). We gathered 147 images on the
nights of 2015 Oct 24 and Nov 1-2. On the night of Oct 31, there
was a transit over a nebula, which resulted in 6 unusable images.
No previous results for a rotation period for 3000 Leonardo have
been published in the LCDB (Warner et al., 2009). The resulting
rotation period of 7.524 ± 0.021 h is consistent with expectations
of main-belt asteroids.
This research was funded by the Astronomy Department at the
University of Maryland, College Park. Additionally, thank you Dr.
Hayes-Gehrke for your assistance in helping us successfully find a
lightcurve for 2343 Siding Spring. We thank Brian Warner at the
Center for Solar System Studies, Palmer Divide Station for helpful
comments in revision of the paper.
References
iTelescope – T7- Deep Field.
http://www.itelescope.net/telescope-t7/
JPL Small Body Database Search Engine
http://ssd.jpl.nasa.gov/sbdb_query.cgi
Acknowledgements
Pollock, J., Caton, D., Hawkins, R., Pravec, P., Pray, D., Cooney,
W., Gross, J., Terrell, D., Oey, J., Benishek, V., Galad, A., Gajdos,
S., Groom, R., Stranger, K., Chiorny, V., Reichart, D., Haislip, J.,
Smith, A. (2015). “(2343) Siding Spring.” CBET 4206.
Funding for observations was provided by the Astronomy
Department at the University of Maryland. We would also like to
thank itelescope.net for the use of their facilities to study this
asteroid.
Pravec, P., Harris, A.W. (1999). “Fast and Slow Rotation of
Asteroids.” Icarus 148, 15.
References
Warner, B.D. (2013). MPO Software. MPO Canopus version
10.4.3.7. Bdw Publishing. http://www.minorplanetobserver.com/
iTelescope (2015). http://www.itelescope.net/
Warner, B.D., Harris, A.W., Pravec, P. (2009). Icarus 202, 134146. Updated 2015 October 10.
http://www.MinorPlanet.info/lightcurvedatabase
120
ASTEROID LIGHTCURVE ANALYSIS AT THE OAKLEY
SOUTHERN SKY OBSERVATORY: 2014 NOVEMBER
Kylie Hess, Richard Ditteon
Rose-Hulman Institute of Technology, CM 171
5500 Wabash Avenue, Terre Haute, IN 47803 USA
[email protected]
(Received: 2015 November 9)
Photometric data were taken over eight nights in 2014
November for six asteroids: 3003 Koncek, 5176 Yoichi,
(5292) 1991 AJ1, 5595 Roth, (6454) 1991 UG1, and
(10565) 1994 AT1.
On the nights of 2014 November 11-14 and 17-20, six asteroids
were targeted from the Oakley Southern Sky Observatory in New
South Wales, Australia. The observations were made using a 0.5-m
Ritchey-Chretien telescope operating at f/8.1 and a STX-16803
camera, binned 3x3, using a luminance filter. The exposure times
were 60 seconds for 5176 Yoichi; 90 seconds for (6454) 1991 UG1
and (10565) 1994 AT1; 120 seconds for 3003 Koncek and (5292)
1991 AJ1; and 180 seconds for 5595 Roth. The image scale was
1.345 arcseconds per pixel. The images were calibrated in MaxIm
DL using dark, bias, and twilight flat frames. The images were then
measured and lightcurves were produced using MPO Canopus.
Periods were determined for 3003 Koncek, (5292) 1991 AJ1, and
(6454) 1991 UG1. We could not determine periods for 5176
Yoichi, 5595 Roth, and (10565) 1994 AT1. For these three objects,
only amplitudes are reported.
Acknowledgements
Calibration and measurement of the images and production of the
lightcurve for (6454) 1991 UG1 were done by Rose-Hulman
student Blake Holeman.
Number
Name
Dates (2014/MM/DD)
Period
(h)
P. Error
(h)
8.023
3003
Koncek
11/11-11/14, 11/17-11/20
5176
Yoichi
11/11-11/14, 11/17-11/20
-
5292
1991 AJ1
11/11-11/14, 11/17-11/20
2.8956
5595
Roth
11/11-11/14, 11/17-11/20
-
6454
1991 UG1
11/11-11/14, 11/17-11/20
9.8017
10565
1994 AT1
11/11-11/14, 11/17-11/20
-
Amplitude
(mag)
A. Error
(mag)
Points
0.002
0.51
0.05
132
-
0.05
0.02
113
0.42
0.05
151
0.10
0.04
124
0.53
0.05
147
0.17
0.04
108
0.0002
0.0012
Table I. Observing circumstances and results.
-
121
LIGHTCURVES FOR
1531 HARTMUT AND 4145 MAXIMOVA
Research and Economic Development Office of New Mexico
Institute of Mining and Technology (NMIMT).
Daniel A. Klinglesmith III
Etscorn Campus Observatory
New Mexico Tech
101 East Road
Socorro, NM 87801 USA
[email protected]
References
AA (2015). Astroart software. http://www.msb-astroart.com/
ECO (2015). Etscorn Campus Observatory.
http://www.mro.nmt.edu/education-outreach/etscorn-campusobservatory
Lorenzo Franco
Balzaretto Observatory (A81)
Rome, ITALY
Harris, A.W., Young, J.W., Bowell, E., Martin, L.J., Millis, R.L.,
Poutanen, M., Scaltriti, F., Zappala, V., Schober, H.J., Debehogne,
H., Zeigler, K. (1989). “Photoelectric Observations of Asteroids 3,
24, 60, 261, and 863.” Icarus 77, 171-186.
CCD photometric observations of minor planets 1531
Hartmut and 4145 Maximova were obtained from 2015
September-December in collaboration from Etscorn
Campus Observatory and Balzaretto Observatory. For
1531 Hartmut, we found a synodic period of P = 25.57 ±
0.01 h and amplitude of A = 0.21 ± 0.03 mag; for 4145
Maximova, the results were P = 19.875 ± 0.002 h and
A ~ 1.0 mag.
CCD photometric observations of two main-belt asteroids were
made on 21 nights from 2015 September 16 to December 1. The
images were obtained at the Etscorn Campus Observatory (ECO,
2015) with three Celestron 0.35-m Schmidt-Cassegrain telescopes
(SCT) on Software Bisque (SB) Paramount ME mounts (SB,
2015). The telescopes were controlled with TheSky6 (SB, 2015).
The CCD cameras were controlled with CCDSoft v5 (SB, 2015).
Exposures were either 300 or 360 seconds through a clear filter
depending on the asteroid’s predicted magnitude. The observations
at Balzaretto Observatory were obtained with a Meade LX-200
0.2-m SCT and SBIG ST-7XME CCD controlled with Astroart v4
(AA, 2015). The exposures were 420 seconds through a clear filter.
JPL (2015). Small Body Database Search Engine.
http://ssd.jpl.nasa.gov/sbdb_query.cgi
SB (2015). http://www.bisque.com/sc/
Warner. B.D. (2015). MPO Canopus software.
http://www.minorplanetobserver.com/MPOSoftware/
MPOCanopus.htm
All images were dark subtracted and flat field corrected using
image processing tools within MPO Canopus version 10.4.7.6
(Warner, 2015). The multi-night data sets for each asteroid were
combined with the FALC routine (Harris et. al., 1989) within MPO
Canopus to provide synodic periods for the asteroid.
1531 Hartmut. This main-belt asteroid was discovered on 1938
September 17 by A. Bohrmann at Heidelberg (JPL, 2015). It was
observed on 12 nights over a time span of 24 days. The derived
synodic period is nearly commensurate with the Earth’s rotation,
P = 25.57 ± 0.01 h with A = 0.21 ± 0.03 mag.
4145 Maximova. This main-belt asteroid was discovered on 1981
September 29 by L.V. Zhuravleva at Nauchnyj (JPL, 2015). It is
also known as 1981 SJ7, 1967 PB, 1974 RC1, and 1981 WB5. It
was observed on 9 nights over a time span of 44 days. The derived
synodic period is P = 19.875 ± 0.002 h with an amplitude of
A ~ 1.0 mag.
A month earlier (Aug 7-15), Pravec et al. (2015) obtained
observations on eight nights for 4145 Maximova and found a
synodic period of 19.872 ± 0.004 h and an amplitude of 0.93 mag.
The two periods and amplitudes agree within the error bars.
Acknowledgements
The Etscorn Campus Observatory operations are supported by the
122
LIGHTCURVE ANALYSIS OF 1654 BOJEVA
Melissa N. Hayes-Gehrke, Devona Austin, Carl Bowers, Andrew
Cleary, Andrew Dilks, Anne Dzurilla, Meir Friedenberg, Sadie
Isakower, Kaydra Davy-Coore, Andrew Kee, Greg Leonhartt,
Sumit Rajpara, Christine Ricciardi, Jacob Wolf, Vivian Zohery
[email protected]
indicate a bimodal lightcurve associated with a rotation period of
10.5559 ± 0.0137 h.
Photometric observations of main-belt asteroid 1654
Bojeva were made over six nights during 2015 October
and November. Remote observations were made using
iTelescope Observatory (MPC H06) in Mayhill, New
Mexico. Lightcurve analysis using MPO Canopus found
a possible rotation period of 10.5559 ± 0.0137 h with an
amplitude of 0.27 mag.
1654 Bojeva is a main-belt asteroid discovered in 1931 by the
Russian astronomer Pelageya F. Shajn. Its semi-major axis is
approximately 3.02 AU, eccentricity 0.09, and orbital period about
5.24 years (JPL, 2015). The asteroid was observed during the
Supplemental IRAS Minor Planet Survey (Tedesco et al., 2004)
and found to have a diameter of 27.0 ± 1.9 km and absolute
magnitude of H = 10.7. It should be noted that previous attempts
have been made to determine 1654 Bojeva’s rotation period. Krotz
et al. (2010) made observations in 2010. However, they could not
determine a repeatable pattern for the asteroid’s lightcurve.
Observations of Bojeva were taken remotely on 2015 Oct 20, 23,
and 31 and Nov 3, 9, and 10 using the T21 telescope at iTelescope
Observatory (H06) in Mayhill, New Mexico. All images were
taken with a 0.43-m Planewave CDK with f/4.5 focal reducer. The
camera was an FLI PL-6303E CCD with 3072x2048 pixels. The
plate scale was 0.96 arcsec/pixel (iTelescope, 2015). Exposure
times were set to 300 s using a luminance filter with the binning
set to 1x1 for all images. Of the 101 images that were recorded, 15
were discarded due to pixel saturation and interference from a
nearby star. During three of the nights, fewer than six usable
images were taken due to inclement weather.
After data were collected and reviewed, MPO Canopus was used
to perform aperture and differential photometry on the images.
Images were calibrated internally by MPO Canopus during this
process. Differential magnitudes were calculated using the Comp
Star Selector utility to select five stars similar in color to the Sun as
reference stars to calculate average magnitudes for each image
(Warner, 2012).
The data from all six nights were plotted as an unphased lightcurve
in MPO Canopus, after which period analysis was conducted. This
uses Fourier analysis to fit the data to many different sinusoidal
curves in order to find the best-fit curve with the smallest rootmean-square (RMS) error value. Adjustments of the magnitude
zero-points for each particular data set were made to achieve the
lowest minimum RMS value in the period spectrum. Four
harmonic terms were chosen since this, coupled with the adjusted
magnitude zero-points, provided the most distinct RMS minimum.
It should be noted that three of our nights yielded only about a
half-dozen usable images. However, these nights were included in
the analysis since they were necessary in plotting a plausible
lightcurve. Additionally, while the overwhelming majority of the
authors independently achieved a rotation period within the
uncertainty of the lightcurve depicted, there was one author whose
analysis yielded a rotation period of 14.3809 ± 0.0268 h. This
difference, along with the aforementioned inclusion of only partial
nights of observation, has caused us to be less confident in our
result than we would like. Additional observations would be
necessary in order to confirm our result.
References
iTelescope (2015). http://itelescope.net/telescope-t21/
Krotz, J., Albers, K., Carbo, L., Kragh, K., Meiers, A., Yim., A.,
Ditteon, R. (2010). “Asteroid Lightcurve Analysis at the Oakley
Southern Sky Observatory.” Minor Planet Bulletin 37, 99-101.
JPL (2015). Small Body Database Browser.
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1654+Bojeva
Tedesco, E.F., Noah, P.V., Noah, M., Price, S.D. (2004). IRAS
Minor Planet Survey. IRAS-A-FPA-3-RDR-IMPS-V6.0. NASA
Planetary Data System.
Warner, B.D., Harris, A.W., Pravec, P. (2009). Icarus 202, 134146. Updated 2015 December 7.
Several possible solutions stood out in the period spectrum.
However, the minimum associated with a solution of 10.56 hours
provided a significantly better fit to the data. The final results
123
LIGHTCURVES FOR SHAPE/SPIN MODELS
Daniel A. Klinglesmith III, Sebastian Hendrickx,
Karl Madden, Samuel Montgomery
New Mexico Tech
101 East Road
Socorro, NM 87801 USA
[email protected]
We obtained lightcurves of 12 asteroids in 2015 for
potential use in shape and spin axis modeling: 855
Newcombia, 929 Algunde, 1730 Marceline, 1967
Menzel, 2074 Shoemaker, 2323 Zverev, 3285 Ruth
Wolfe, 3640 Gostin, 3682 Welther, 3873 Roddy,
(6823) 1988 ED1, and (11424) 1999 LZ24.
In order to obtain an initial model for the shape of an asteroid, it is
usually necessary to obtain lightcurves from at least 3 or 4
oppositions with different phase angle bisector longitudes (see
Harris et al., 1984). For main-belt asteroids, this usually means
observations from several successive oppositions. In the last article
in each Minor Planet Bulletin, Warner et al. (e.g., 2015) provide a
list of possible shape/spin candidates. We chose to attempt to
obtain lightcurves from their most recent article where the known
periods were less than 4 hours. This gave us the chance to obtain at
least one complete period cycle per night.
Our observations were obtained with the three Celestron 0.35-m
telescopes and SBIG cameras at Etscorn Campus Observatory
(Klinglesmith, 2015). The images were processed and calibrated
using MPO Canopus 10.4.7.6 (Warner, 2015). The exposures were
between 180 and 360 seconds through clear filters. The multi-night
data sets for each asteroid were combined with the FALC routine
(Harris et al., 1989) within MPO Canopus to provide synodic
periods for each asteroid.
The information about the discovery and names were obtained
from the JPL Small Body Database Search Engine (JPL, 2015).
The previously obtained periods and phase angle bisector
longitudes and latitudes (LPAB and BPAB) were obtained from the
asteroid lightcurve database (LCDB; Warner et al., 2009) and
listed in Table I along with our results.
855 Newcombia is a main-belt asteroid discovered by S.
Belyavskij at Simeis on 1916 Apr 3. An independent discovery
was made by M. Wolf at Heidelberg on 1916 Apr 28. It is also
known as 1916 ZP. Our results for the period and amplitude are
P = 3.004 ± 0.001 h, A = 0.41 mag.
929 Algunde is a Flora asteroid discovered by K. Reinmuth at
Heidelberg on 1920 Mar 10. It is also known as 1920 GR. Our
results for the period and amplitude are P = 3.310 ± 0.001 h,
A = 0.14 mag.
1730 Marceline is a main-belt asteroid discovered by M. Laugier at
Nice on 1936 Oct 17. It is also known as 1936 UA, 1931 RE, 1950
WF, 1952 DR2, 1954 QA, and 1971 JC. Our results for the period
and amplitude are P = 3.837 ± 0.001 h, A = 0.59 mag.
1967 Menzel is a Flora asteroid discovered by M. Wolf at
Heidelberg on 1905 Nov 1. It is also known as A905 VC,
1930 DS, 1965 SF, 1965 VH, 1970 EM, 1973 CE, 1975 UH, and
1975 VE. Our results for the period and amplitude are P = 2.835 ±
0.001 h, A = 0.29 mag.
2074 Shoemaker is a Hungaria asteroid discovered by E.F. Helin at
Palomar on 1974 Oct 17. It is also known as 1974 UA. Our results
for the period and amplitude are P = 2.534 ± 0.001 h,
A = 0.06 mag.
2323 Zverev is a main-belt asteroid discovered by N. Chernyhk on
1976 Sep 24 at Nauchnjy. It is also known as 1976 SF2, 1951 GP,
1960 WK, 1965 SW, and 1965 UF1. Our results for the period and
amplitude are P = 3.923 ± 0.003 h, A = 0.37 mag.
3285 Ruth Wolfe is a main-belt asteroid discovered by C.
Shoemaker and E. Shoemaker on 1983 Nov 5 at Palomar. It is also
known as 1983 VW1, 1952 BR, 1979 VP1, and 1979 YR1. Our
results for the period and amplitude are P = 3.939 ± 0.001 h,
A = 0.20 mag.
3640 Gostin is a Flora asteroid discovered by C. Shoemaker and E.
Shoemaker on 1985 Oct 11. It is also known as 1985 TR3,
1955 SS, 1960 CB, 1970 CS, and 1972 VJ1. Our results for the
period and amplitude are P = 3.263 ± 0.003 h, A = 0.27 mag.
3682 Welther is a main-belt asteroid discovered by K. Reinmuth at
Heidelberg on 1923 Jul 12. It is also known as A923 NB,
1951 YO, 1978 NP3, and 1984 AA. Our results for the period and
amplitude are P = 3.599 ± 0.003 h and A = 0.37 mag.
3873 Roddy is a main belt asteroid discovered by C. Shoemaker at
Palomar on 1984 Nov 21. It is also known as 1984 WB and
1953 XK1. Our results for the period and amplitude are P = 2.479
± 0.001 h, A = 0.08 mag.
(6823) 1988 ED1 is main-belt asteroid discovered by M. Arai and
H. Mori at Yorii on 1988 Mar 12. Our results for the period and
amplitude are P = 2.546 ± 0.001 h, A = 0.13 mag.
(11424) 1999 LZ24 is a main belt asteroid discovered by LINEAR
at Socorro on 1999 Jun 09. It is also known 1955 XJ, 1970 YA,
1991 JH6, and 1998 GM2. Our results for the period and amplitude
are P = 2.927 ± 0.003 h, A = 0.13 mag.
References
Albers, K., Kragh, K., Monnier, A., Pligge, Z., Stolze, K., West, J.,
Yim, A., Ditteon, R. (2010). “Asteroid Lightcurve Analysis at the
Oakley Southern Sky Observatory: 2009 October thru 2010 April.”
Aymami, J.M. (2011). “CCD Photometry and Lightcurve Analysis
of 1730 Marceline and 1996 Adams from Observatori Carmelita in
Tiana.” Minor Planet Bull. 38, 55-56.
Behrend, R. (2001, 2005, 2006, 2008, 2010, 2011)
Brinsfield, J.W. (2011). “Asteroid Lightcurve Analysis at the Via
Capote Observatory: 4th Quarter 2010.” Minor Planet Bull. 38, 7374.
Chang, C.-K., Ip, W.-H., Lin, H.-W., Cheng, Y.-C., Ngeow, C.-C.,
Yang, T.-C., Waszczak, A., Kulkarni, S.R., Levitan, D., Sesar, B.,
Laher, R., Surace, J., Prince, T.A. (2014). “313 New Asteroid
Rotation Periods from Palomar Transient Factory Observations.”
Ap. J. 788, A17.
124
Clark, M. (2015). “Asteroid Photometry from the Preston Gott
Warner, B.D. (2001). “Asteroid Photometry at the Palmer Divide
Cooney Jr., W.R., Gross, J., Terrell, D., Reddy, V., Dyvig, R.
(2007). “Lightcurve Results for 486 Cremona, 855 Newcombia
942 Romilda, 3908 Nyx, 5139 Rumoi, 5653 Camarillo, (102866)
1999 WA5.” Minor Planet Bull. 34, 47-48.
Warner, B.D. (2003). “Lightcurve analysis of asteroids 331, 795,
886, 1266, 2023, 3285, and 3431.” Minor Planet Bull. 30, 61-64.
Durkee, R.I., Ferrero, A. (2011). “The Lightcurve of Asteroid 4223
Shikoku.” Minor Planet Bull. 38, 40-41.
Galad, A., Kornos, L. (2008). “A Sample of Lightcurves from
Modra.” Minor Planet Bull. 35, 78-81.
Harris, A.W., Young, J.W., Scaltriti, F., Zappala, V. (1984).
“Lightcurves and phase relations of the asteroids 82 Alkmene and
444 Gyptis.” Icarus 57, 251-258.
24, 60, 261, and 863.” Icarus 77, 171-186.
Higgins, D. (2008). “Asteroid Lightcurve Analysis at Hunters Hill
Observatory and Collaborating Stations: April 2007 - June 2007.”
Warner, B.D. (2005). “Revised lightcurve analysis for 1022
Olympiada and 3285 Ruth Wolfe.” Minor Planet Bull. 32, 26.
Warner, B.D. (2006). Asteroid lightcurve analysis at the Palmer
Divide Observatory - late 2005 and early 2006.” Minor Planet
Bull. 33, 58-62.
Warner, B.D. (2008). “Asteroid Lightcurve Analysis at the Palmer
Divide Observatory - June - October 2007.” Minor Planet Bull. 35,
56-60.
Divide Observatory: 2009 March-June.” Minor Planet Bull. 36,
172-176.
Warner, B.D., Harris, A.W., Pravec, P. (2009). Icarus 202, 134146. Updated 2015 December 7.
Warner, B.D. (2011a). “A Quartet of Known and Suspected
Hungaria Binary Asteroid.” Minor Planet Bull. 38, 33-36.
Hummel, J., Postma, A., Sumter, G.C., Moore, H., Sweet, S.,
Beaky, M.M. (2008). “Lightcurve Analysis of Asteroids 3036
Krat, 3285 Ruth Wolfe, and 5448 Siebold.” Minor Planet Bull. 35,
160-161.
Warner, B.D. (2011b). “Upon Further Review: III. An
Examination of Previous Lightcurve Analysis from the Palmer
Divide Observatory.” Minor Planet Bull. 38, 21-23.
Klinglesmith III, D.A., Hanowell, J., Risley, E., Turk, J., Vargas,
A., Warren, C.A. (2014). “Lightcurves for Inversion Model
Candidates.” Minor Planet Bull. 41, 139-143.
Warner, B.D. (2011c). “Upon Further Review: V. An Examination
of Previous Lightcurve Analysis from the Palmer Divide
Klinglesmith III, D.A., DeHart, A., Hanowell, J., Hendrickx, S.
(2015). “Asteroids at Etscorn Campus Observatory: 2014
September–December.” Minor Planet Bull. 42, 101–104.
Warner, B.D. (2011d). “Asteroid Lightcurve Analysis at the
Palmer Divide Observatory: 2010 September-December.” Minor
Planet Bull. 38, 82-86.
LeCrone, C., Duncan, A., Hudson, E., Johnson, J., Mulvihill, A.,
Rechert, C., Ditteon, R. (2006). “2005-2006 fall observing
campaign at Rose-Hulman Institute of Technology.” Minor Planet
Bull. 33, 66-67.
Warner, B.D., Stephens R. (2012). “Lightcurve for 2074
Shoemaker.” Minor Planet Bull. 39, 225.
Liu, J. (2016). “Rotation Period Analysis for 1967 Menzel.” Minor
Oey, J. (2008). Lightcurve Analysis of Asteroids from the
Kingsgrove and Leura Observatories in the 2nd Half of 2007.”
Pravec, P., Wolf, M., Sarounova, L. (2007, 2008, 2010)
Pray, D., Pravec, P., Kusnirak, P., Nudds, S., Galad, A., Gajods, S.,
Vilagi, J., Koff, R. (2006). “(4786) Tatianina.” CBET 472.
Warner, B.D. (2013). “Rounding Up the Unusual Suspects.” Minor
Warner, B.D. (2015). MPO Canopus software.
http://bdwpublishing.com/mposoftware.aspx
Warner, B.D., Harris, A.W., Ďurech, J., Benner, L.A.M. (2015).
“Lightcurve Photometry Opportunities 2015 October–December.”
Minor Planet Bull. 42, 286–290.
Warner, B.D. (2016). “Asteroid Lightcurve Analysis at CS3Palmer Divide Station: 2015 June-September.” Minor Planet Bull.
43, 57-65.
Stephens, R.D., Warner, B.D., Pravec, P., Kusnirak, P., Sarounova,
L., Wolf, M., Malcolm, G. (2002). “Lightcurves of 3682 Welther.”
Stephens, R.D. (2008). “Asteroids Observed from GMARS and
Santana Observatories - Late 2007 and Early 2008.” Minor Planet
Bull. 35, 126-127.
125
126
127
Number
855
929
1730
1967
2074
2323
3285
3640
Name
Newcombia
Algunde
Marceline
Menzel
Shoemaker
Zverev
Ruth Wolfe
Gostin
Reference
Date
LPAB
BPAB
Phase
Period
Amp
Cooney 2007
2004 Oct 14
9.0
-1.4
5.9
3.003
0.35
Klinglesmith 2014
2014 Apr 01
197.8
1.8
12.9
3.003
0.33
this paper
2015 Nov 10
20.8
2.3
11.6
3.004
0.41
Galad 2008b
2008 Mar 18
143.1
-5.0
17.4
3.31016
0.00
Pravec 2008web
2008 Mar 02
330.9
5.5
13
3.3107
0.02
Behrend 2008web
2008 Aug 14
331.6
5.6
7.1
6.619
0.19
Oey 2008e
2008 Aug 01
330.9
5.5
13.5
3.311
0.13
this paper
2015 Oct 12
16.6
3.0
1.8
3.31
0.14
Aymami 2001a
2010 Sep 12
343.6
1.5
3.1
3.837
1.00
Behrend 2010web
2010 Sep 26
344.2
0.5
10
2.8366
1.00
Brinsfield 2011a
2010 Sep 03
343.3
2.1
2
3.836
0.94
this paper
2015 Nov 03
45.7
-10.6
7.7
3.837
0.59
Pray et al. 2006
2005 Sep 24
19.4
-4.1
12.6
2.835
0.28
LeCrone et al. 2006
2005 Nov 02
22.5
-2.9
11.6
2.834
0.38
Pravec et al. 2007
2007 Apr 10
194.7
3.5
3.1
2.8344
0.24
Higgins 2008
2007 Apr 10
194.7
3.5
3.1
2.8346
0.25
Behrend 2005
2005 Oct 27
194.7
3.5
3.1
2.83481
0.27
Pravec et al. 2010
2010 Jan 14
150.7
5.0
18.8
2.8343
0.27
Clark 2015
2014 Jun 14
230.3
0.0
15.2
2.8346
0.25
Liu 2016
2015 Oct 11
18.1
-3.8
2.7
2.84
0.39
this paper
2015 Nov 05
20.2
-2.9
13.5
2.835
0.29
Warner 2009
2009 Oct 18
22.0
4.4
4.2
2.5328
0.06
Warner 2011b
2010 Jul 24
312.1
43.4
28.3
2.5338
0.12
Warner 2012
2012 Apr 05
219.7
3.7
16.2
2.82
0.08
Warner 2016
2015 Jun 25
341.7
32.6
34.5
2.809
0.13
this paper
2015 Oct 08
3.5
18.1
16.8
2.534
0.06
Behrend 2006
2006 Jan 08
140.5
4.5
13.4
3.9213
0.39
Behrend 2011
2011 Jan 01
74.1
5.6
11.2
3.92114
0.36
Waszczak et al. 2015
2011 Jan 13
74.8
5.5
15.9
3.9215
0.38
this paper
2015 Nov 08
18.1
1.7
10.1
3.923
0.37
Warner 2003
1999 Nov 03
41.2
13.6
Warner 2005
1999 Nov 04
41.2
13.4
Hummel et al. 2008
2007 Nov 02
32.9
16.2
Warner 2011c
1999 Nov 04
41.2
13.4
this paper
2015 Oct 10
25.1
21.1
Albers et al. 2010
2010 Mar 10
165.5
Chang et al. 2014
2013 Feb 16
112.6
2013 Feb 11
this paper
2015 Nov 05
8.8
6.722
0.21
8.7
3.94
0.20
11.1
3.919
0.20
8.7
3.937
0.20
14
3.939
0.20
-5.2
4.1
3.2641
0.40
-1.3
19.6
3.26
0.47
119.9
-1.2
17.6
3.2632
0.37
47.0
5.6
4.7
3.263
0.27
Table 1, part 1: Previously published phase angle bisectors, synodic periods, and amplitudes from the Lightcurve Data
Base (LCDB, Warner, 2015) plus results from this paper
128
Number
3682
3873
6823
11424
Name
Welther
Roddy
1988 ED1
1999 LZ24
Reference
Date
LPAB
Stephens et al. 2002
2001 Sep 07
348.2
Behrend 2001
2001 Aug 25
345.0
2001 Oct 03
BPAB
Phase
Period
Amp
30.6
14.7
3.5973
0.21
20.2
16
3.603
0.33
350.7
19.8
18.3
0.26
2001 Oct 06
351.3
19.6
19.3
0.28
2001 Oct 12
352.7
19.0
21
Behrend 2001
2001 Oct 13
352.7
19.0
21.3
3.595
0.28
Behrend 2010
2010 Aug 09
310.0
16.5
10.9
3.5973
0.22
this paper
2015 Nov 04
60.9
7.1
13.3
3.599
0.37
Warner 2006
2005 Dec 05
113.3
-17.0
28.7
2.4782
0.09
Warner 2008
2007 Aug 16
355.9
30.7
22.9
2.4792
0.10
Warner 2009
2009 Jun 20
251.8
5.0
12.4
2.48
0.06
Warner 2011d
2010 Nov 29
68.3
1.7
1.7
2.4782
0.05
Warner 2013
2007 Aug 26
356.7
31.2
21
2.479
0.11
Warner 2013
2012 Aug 30
11.5
32.4
19.1
2.479
0.08
Warner 2016
2015 Jul 09
11.5
23.7
28.1
2.486
0.10
this paper
2015 Nov 02
30.5
20.5
14.5
2.479
0.08
Stephens 2008
2007 dec 28
91.8
2.5
2.6
2.541
0.1
Behrend 2011
2008 Jan 12
92.3
4.3
10.3
2.598
0.3
Durkee 2012
2011 Dec 10
74.2
-4.8
3.3
2.546
0.19
2013 Mar 12
200.6
19.5
13.7
2.546
0.19
this paper
2015 Nov 05
54.6
-14.0
11.9
2.546
0.14
Warner 2001
2000 Nov 25
60.0
-2.1
2.3
2.928
0.11
Warner 2011b
2000 Nov 25
60.0
-2.1
2.3
2.925
0.08
2013 Aug 24
198.3
7.9
13.8
2.9275
0.10
this paper
2015 Nov 07
58.8
-4.3
9.7
2.927
0.13
0.31
Table 1, part 2: Previously published phase angle bisectors, synodic periods, and amplitudes from the Lightcurve Data
Base (LCDB, Warner, 2015) plus results from this paper.
129
NIR MINOR PLANET PHOTOMETRY
FROM BURLEITH OBSERVATORY, 2015
Richard E. Schmidt
Burleith Observatory (I13)
1810 35th St NW
Washington, DC 20007
[email protected]
Despite residing in one of the more light-polluted urban
areas of the U.S., the 0.32-m Burleith Observatory
telescope is able to determine minor planet rotation
periods consistent with more optimally-located
observatories. In 2015, rotation periods were obtained
for six minor planets: 337 Devosa, 1016 Anitra, 2379
Heiskanen, 3987 Wujek, 4012 Geballe, and 5236 Yoko.
Fig. 2. Mean signal/noise ratios as a function of magnitude
Washington, DC has the distinction of being in one of the more
light-polluted areas of the United States (Fig. 1; Lorenz, 2015).
A PlaneWave 0.32-m f/8 CDK astrograph was equipped with an
SBIG STL-1001E CCD camera and an Astrodon Cousins Ic filter
that provides a NIR bandwidth of 700-900 nm. The unbinned
image scale of 1.95 arc-seconds per pixel is well-matched to the
typical 4 to 5 arc-second seeing. All observations of this program
were autoguided and bias and sky flat-field corrected using
CCDSoft version 5.00.217. Photometry and period analysis were
performed using MPO Canopus version 10.7.0.1 (Warner, 2015).
The Comp Star Selector (CSS) utility was used to select
comparison stars with solar-like spectra. Solutions were checked
using Peranso software version 2.51 (Vanmunster, 2015) using the
FALC (Harris et al., 1989) and ANOVA (Schwarzenberg-Czerny,
1996) methods.
337 Devosa. Discovered in 1892 by A. Charlois at Nice, this minor
planet provided its name for the 1944 christening of the USS
Devosa (AKA-27), an attack cargo ship. H.J. Schober reported its
unusual triple extrema (Schober, 1979). The observed period
below agrees with Behrend (2010). Peranso FALC gives 4.6051
±0.0027 h; Peranso ANOVA gives 4.5726 ± 0.0016 h.
Fig. 1. Location of Burleith Observatory in the Light Pollution Atlas,
2006. The four brightest night sky areas (Washington, Baltimore,
Philadephia, New York City) are shown in white.
In 2015 December, the sky background was measured as 18.50 ±
0.04 mag/arcsec2 (Ic) using synthetic aperture photometry with
Mira AP software version 7.974 (Mirametrics, 2015). This
brightness, 25 times brighter than the skies at Mauna Kea, results
in high background noise and limits longer exposures. Some
example mean object signal-to-noise (SNR) values from MPO
Canopus are shown in Figure 2. Despite these limitations, it is
possible to do useful minor planet differential photometry with a
modest telescope in a fiberglass dome mounted on top of an urban
house surrounded by neighbors, street lights, and traffic.
Number
Name
1016 Anitra. This asteroid was discovered by Karl Reinmuth at the
Heidelberg-Königstuhl State Observatory in 1924 at photographic
mag 13.3. (Leuschner, 1935). Reinmuth retired in 1957 as the
current most prolific minor planet finder in history with 395
confirmed discoveries (Minor Planet Center, 2015). Anitra is a
member of the Flora family of S-type main-belt asteroids
(Kryszczynska et al., 2012). Menke (2005) observed Anitra,
finding a period of 5.9300 ± 0.0003 h, consistent with subsequent
observers (Pray et al., 2006; Alkema, 2013). Peranso FALC gives
Obs.Date Range
2015
(mm/dd)
Images
Exp.
(s)
Phase
(°)
Period
(h)
P.E.
(h)
Amp
Ic
(mag)
A E
Ic
(mag)
337
Devosa
01/29 – 03/25
501
90,120
6.7–25.4
4.6528
0.0001
0.33
0.01
1016
Anitra
10/20 – 11/09
557
300
1.82-12.45
5.9301
0.0003
0.27
0.03
2379
Heiskanen
11/26 – 12/20
180
420
23.4–23.9
3.7627
0.0003
0.23
0.05
3987
Wujek
11/21 – 11/23
96
300
6.4-7.4
8.036
0.014
0.36
0.04
4012
Geballe
12/05 – 12/19
104
420
8.3-15.7
5.8864
0.0064
0.90
0.05
5236
Yoko
11/13 – 11/20
96
300
6.4–10.3
2.7692
0.0004
0.44
0.05
130
5.9300 ± 0.0070 h; Peranso ANOVA gives 5.9302 ± 0.0040 h.
2379 Heiskanen was discovered in 1941 by Yrjö Väisälä, one of
128 minor planets discovered within 31 months at Turku, Finland.
The LCDB (Warner et al., 2009) reports a recent 3.76 h period by
Garceran et al. (2016). Peranso FALC gives 3.7613 ± 0.0075 h;
Peranso ANOVA gives 3.7626 ± 0.0028 h.
3987 Wujek was discovered in 1986 by E. Bowell at Anderson
Mesa. No prior results were found in the LCDB (Warner et al.,
2009). Peranso FALC gives 8.0460 ± 0.3246 h; Peranso ANOVA
gives 7.4410 ±0.1437 h. Clearly, more observations are needed.
4012 Geballe was discovered in 1978 by E. Helin and S. Bus at
Palomar. The period below agrees with the more precise result by
Pravec et al. (2015) of 5.88597 h. Peranso FALC gives 5.8846 ±
0.0066 h; Peranso ANOVA gives 5.8839 ± 0.0028 h.
5236 Yoko. Y. Mizuno and T. Furuta at Kani discovered Yoko in
1990. A period of 2.768 h was reported by Carbo et al. (2009).
Peranso FALC gives 2.7701 ± 0.0051 h; Peranso ANOVA gives
2.7696 ± 0.0041 h.
Lorenz,
D.
(2015).
“Light
Pollution
Atlas
2006.”
http://http://djlorenz.github.io/astronomy/lp2006/, accessed Dec.
2015.
Menke, J. (2005). “Lightcurves and periods for asteroids 471
Papagena, 675 Ludmilla, 1016 Anitra, 1127 Mimi, 1165
Imprinetta, 1171 Rustahawelia, and 2283 Bunke.” Minor Planet
Bull. 32, 64-66.
Minor Planet Center. (2015).
http://www.minorplanetcenter.net/iau/lists/MPDiscsNum.html
Mirametrics. (2015). http://www.mirametrics.com/mira_ap.htm
Pray, D.P., Galad, A., Gajdos, S., Vilagi, J., Cooney, W., Gross, J.,
Terrel, D., Higgins, D., Husarik, M., Kusnirak, P. (2006).
“Lightcurve analysis of asteroids 53, 698, 1016, 1523, 1950, 4608,
5080 6170, 7760, 8213, 11271, 14257, 15350 and 17509.” Minor
Acknowledgements
Schober, H.J. (1979). “Rotation period of the Minor Planet 337
Devosa - an unusual object with triple extrema in the photoelectric
lightcurve.” Astron. Astrophys. Suppl. 35, 337-343.
The author acknowledges with gratitude the helpful advice and
instruction of Frederick Pilcher, Organ Mesa Observatory, and
wishes to acknowledge again B. D. Warner for his invaluable
contributions to the growth of amateur minor planet photometry.
Schwarzenberg-Czerny, A. (1996). “Fast and Statistically Optimal
Period Search in Uneven Sampled Observations.” Ap. J. 460,
L107-110.
References
Vanmunster, T. (2015). Peranso software. CBA Belgium
Observatory. http://www.cbabelgium.com
Alkema, M.S. (2013). “Asteroid Lightcurve Analysis at Elephant
Head Observatory: 2012 November - 2013 April.” Minor Planet
Bull. 40, 133-137.
Carbo, L., Green, D., Kragh, K., Krotz, J., Meiers, A., Patino, B.,
Pligge, Z., Shaffer, N., Ditteon, R. (2009). “Asteroid Lightcurve
Analysis at the Oakley Southern Sky Observatory: 2008 October
thru 2009 March.” Minor Planet Bull. 36, 152-157.
Garceran, A.C., Aznar, A,. Mansego, E.A., Rodriguez, P.B., de
Haro, J.L., Silva, A.F., Silva, G.F., Martinez, V.M., Chiner, O.R.
(2016). “Nineteen Asteroids Lightcurves at Asteroids Observers
(OBAS) - MPPD: 2015 April – September.” Minor Planet Bull.
43, 92-97.
lightcurve database.” Icarus 202, 134-146. Updated 2015
December 7.
Warner, B.D. (2015). MPO Canopus software. Bdw Publishing,
http://www.MinorPlanetObserver.com
Helou, G., Prince, T.A., Kulkarni, S. (2015). “Asteroid Light
Curves from the Palomar Transient Factory Survey: Rotation
Periods and Phase Functions from Sparse Photometry.” Astron. J.
150, A75.
H., Zeigler, K.W. (1989). “Photoelectric Observations of Asteroids
3, 24, 60, 261, and 863.” Icarus 77, 171-186.
Kryszczynska, A., Colas, F., Polinksa, M., Hirsch, R., Ivanova, V.,
Apostolovska, G., Bilkina, B., Velichko, F.P. Kwaitokski, T.,
Kaniewicz, P. and 20 coauthors. (2012). “Do Slivan states exist in
the Flora family?. I. Photometric survey of the Flora region.”
Astron. Astrophys. 546, 72.
Leuschner, A. (1935). Research Surveys of the Orbits and
Perturbations of Minor Planets 1 to 1091 from 1801.0 to 1929.5,
p. 501. Univ. California Press, Berkeley.
131
132
ASTEROID PHOTOMETRY FROM THE
PRESTON GOTT OBSERVATORY
6326 Idamiyoshi The period derived here is in excellent agreement
with that derived by Waszczak et al. (2015).
Dr. Maurice Clark
Department of Physics
Texas Tech University
Lubbock TX 79409 USA
[email protected]
7192 Cieletespace. The period given here is somewhat longer than
that found by Waszczak et al. (2015). However, the current result
is derived from only two nights of data.
(9465) 1998 HJ121. The period derived here is in excellent
agreement with that from Waszczak et al. (2015).
Asteroid lightcurve period and amplitude results
obtained at the Preston Gott Observatory during the
second half of 2015 are presented.
The Preston Gott Observatory is the main astronomical facility of
the Texas Tech University. Located about 20 km north of
Lubbock, the main instrument is a 0.5-m f/6.8 Dall-Kirkham
Cassegrain. An SBIG STL-1001E CCD was used with this
telescope. Other telescopes used were 0.35-m and 0.30-m SchmidtCassegrains, each equipped with SBIG ST-9XE CCD’s. All
images were unfiltered and were reduced with dark frames and sky
flats.
Image analysis was accomplished using differential aperture
photometry with MPO Canopus. Period analysis was also done in
MPO Canopus, which implements the algorithm developed by
Alan Harris (Harris et al., 1989). Differential magnitudes were
calculated using reference stars from the USNO-A 2.0 catalog and
the UCAC4 catalog.
Results are summarized in the table below and the lightcurve plots
are presented at the end of the paper. The data and curves are
presented without additional comment except were circumstances
warrant.
5240 Kwasan. Observations of this asteroid were made on two
nights before clouds and work prevented further observations. The
derived period is somewhat longer that that found by earlier studies
(Ivanova, 2002, 5.35 ± 0.01 h;
Behrend, 2010, 5.50 ±
0.01 h; Albers, 2010, 5.676 h) This is clearly an asteroid that needs
further work to a find an unambiguous period.
#
5240
6326
6538
7192
9465
12614
13143
13762
15520
16849
22977
23692
25638
46989
52748
Name
Kwasan
Idamiyoshi
Muraviov
Cieletespace
1998 HJ 121
Hokusai
1995 AF
1998 SG130
1999 XK98
1997 YV
1999 VF24
1997 KA
Ahissar
1998 TO5
1998 JJ1
Date
2015
09/09
09/13
10/11
07/19
09/09
11/01
09/13
09/13
07/19
11/01
07/19
11/01
09/13
11/22
11/08
Range
mm/dd
– 09/13
– 10/13
– 12/15
– 08/14
– 09/13
– 11/13
- 10/18
- 10/18
– 08/13
– 12/17
– 08/14
– 12/17
– 10/18
– 12/17
– 12/06
12614 Hokusai. Behrend (2005) reported a rotation period of 2.87
hours. The result derived here rules that period out completely.
(52748) 1998 JJ1. The period derived here closely matches that
derived by Stephens (2015)
Acknowledgments
I would like to thank Brian Warner for all of his work with the
program MPO Canopus and for his efforts in maintaining the
CALL website (http://www.minorplanet.info/call.html).
References
Behrend, R. (2005, 2010). Observatoire de Geneve web site.
Albers, K., Kragh, K., Monnier, A., Pligge, Z., Stolze, K. West, J.,
Yim, A., Ditteon, R. (2010). “Asteroid Lightcurve Analysis at the
Oakley Southern Sky Observatory: 2009 October Thru 2010
April.” Minor Planet Bull. 37, 152-158.
Ivanova, V.G., Apostolovska, G., Borisov, G.B., Bilkina, B.I.
(2002). “Results from Photometric Studies of Asteroids at Rozhen
National Observatory, Bulgaria.” in: Proceedings of Asteroids,
Comets, Meteors - ACM 2002. (B. Warmbein, ed.). ESA SP-500.
pp 505–508.
Stephens, R.D. (2015). Published in the asteroid lightcurve
database.
Warner, B.D., Harris, A.W., Pravec, P. (2009). Icarus 202, 134146. Updated 2015 Dec 7.
Nights
2
4
3
5
2
3
5
4
4
5
6
5
3
5
2
Per
(h)
5.909
3.138
2.9759
6.3546
5.802
2.7296
4.9813
2.7587
8.7904
6.0472
4.532
10.430
3.2721
9.0420
4.3260
Error
(h)
0.001
0.001
0.0001
0.0004
0.002
0.0004
0.0002
0.0001
0.0004
0.0001
0.001
0.002
0.0001
0.0005
0.0002
Amp.
(mag)
0.49
0.31
0.24
0.44
0.65
0.80
0.27
0.25
0.73
0.68
0.13
0.25
0.66
0.72
0.78
A.E.
0.03
0.05
0.1
0.1
0.1
0.05
0.03
0.03
0.1
0.1
0.05
0.1
0.05
0.1
0.1
Table I. Observing circumstances and results. Column 3 gives the range of dates of observations and column 4
gives the number of nights on which observations were undertaken.
133
150, A75.
134
135
ROTATION PERIOD DETERMINATIONS FOR
269 JUSTITIA, 275 SAPIENTIA, 331 ETHERIDGEA,
AND 609 FULVIA
Frederick Pilcher
Las Cruces, NM 88011 USA
[email protected]
(Received: 2016 January 5)
The synodic rotation periods and amplitudes are reported
for 269 Justitia 33.128 ± 0.001 hours, 0.25 ± 0.01
magnitudes; 275 Sapientia 14.932 ± 0.001 hours, 0.10 ±
0.01 magnitudes; 331 Etheridgea 25.315 ± 0.001 hours,
0.12 ± 0.01 magnitudes; 609 Fulvia 35.375 ± 0.001
hours, 0.21 ± 0.02 magnitudes.
Observations to produce these determinations for the minor planets
reported here have been made at the Organ Mesa Observatory with
a 35.4 cm Meade LX200 GPS S-C and SBIG STL 1001-E CCD.
Photometric measurement and lightcurve construction are with
MPO Canopus software. All exposures are 60 second exposure
time, unguided, clear filter. To reduce the number of points on the
lightcurves and make them easier to read data points have been
binned in sets of 3 with maximum time difference 5 minutes.
269 Justitia. Previous rotation period determinations have been
made by Barucci et al. (1992), 16.545 hours; and by Behrend
(2006), 26.3 hours. New observations on 11 nights 2015 Nov. 21 –
2016 Jan. 3 provide a good fit to an irregular bimodal lightcurve
with period 33.128 ± 0.001 hours and amplitude 0.25 ± 0.01
magnitudes. This is twice the Barucci et al (1992) estimate and
also disagrees with Behrend (2006).
275 Sapientia. Previous rotation period determinations have been
made by Denchev (2000), >20 hours; Behrend (2006), 24.07
hours; Warner (2007), 14.766 hours; and Pilcher (2015), 14.931
hours. With the period already well established by the dense
lightcurve of Pilcher (2015), it was possible to cover the entire
lightcurve twice and the double period lightcurve once with
observations on 5 carefully selected nights 2015 Sept. 28 – Nov.
20. These observations provide a good fit to a lightcurve with
period 14.932 ± 0.001 hours, amplitude 0.10 ± 0.01 magnitudes.
This result is completely consistent with Pilcher (2015), close to
the period by Warner (2007), and rules out all other previously
published periods.
136
331 Etheridgea. Previous rotation period determinations have been
made by Warner (2003), 6.82 hours; and by Behrend (2004), 13.54
hours. Warner (2010) reevaluated his earlier data with greatly
improved software and concluded that the period was likely to be
much longer than the originally published 6.82 hours. Alkema
(2013) found a period 13.092 hours. New observations on 18
nights 2015 Sept. 13 – Nov. 18 provide a good fit to an asymmetric
lightcurve with period 25.315 ± 0.001 hours with one deep
minimum and one shallow minimum. An upward bump in the
shallow minimum had a height about 0.02 magnitudes 2015 Sept.
13-14 at phase angle 18 degrees. Its height decreased with
decreasing phase angle and the bump had disappeared 2015 Nov.
6-8 at phase angle 2 degrees. Future lightcurve inversion shape
modelers can expect to find an interesting topographic feature by
modeling this bump. The new 25.315 hour period is completely
inconsistent with all previously published periods.
References
Alkema, M.S. (2013). “Asteroid Lightcurve Analysis at Elephant
Head Observatory: 2012 November – 2013 April.” Minor Planet
Bull. 40, 133-137.
Barucci, M. A., Di Martino, M., Fulchignoni, M. (1992). Astron.
J. 103, 1679-1686
Behrend, R. (2004).
Observatoire de Geneve web site,
http://obswww.unige.ch/~behrend/page_ou.html.
Behrend, R. (2006).
Observatoire de Geneve web site.
http://obswww.unige.ch/~behrend/page_cou.html.
Behrend, R. (2007).
Observatoire de Geneve web site:
Denchev, P. (2000). "Photometry of 11 asteroids during their 1998
and 1999 apparitions." Planet Space Sci. 48, 987-992.
Pilcher, F. (2015). “Rotation Period Determinations for 275
Sapientia, 309 Fraternitas, and 924 Toni.” Minor Planet Bull 42,
38-39.
Warner, B.D. (2003). “Lightcurve Analysis of Asteroids 331, 795,
886, 1266, 2023, 3285, and 3431.” Minor Planet Bull. 30, 61-64.
Warner, B.D. (2007). "Asteroid Lightcurve Analysis at the Palmer
Divide Observatory-December 2006-March 2007." Minor Planet
Bull. 34, 72-77.
Warner, B.D. (2010). “Upon Further Review: I. An Examination
of Previous Lightcurve Analysis from the Palmer Divide
609 Fulvia. Previous rotation period determinations are by
Behrend (2006), >12 hours; again by Behrend (2007), > 12 hours;
and by Waszczak et al. in the Palomar Transient Factory (PTF)
Survey (2015), 34.9857 hours. New observations on 11 nights
2015 Oct. 23 – Dec. 19 provide a good fit and full phase coverage
to a lightcurve with period 35.375 ± 0.001 hours, amplitude 0.21 ±
0.02 magnitudes. This is significantly greater than the period
derived from sparse data by Waszczak et al. This project also
shows that, despite the large number of sparser asteroid lightcurves
being produced by the PTF, dense photometry by telescopes of 25
cm to 40 cm aperture continues to be highly productive.
Waszczak, A., Chang, C.-K., Ofek, E.O., Laher, F., Masci, F.,
Levitan, D., Surace, J., Cheng, Y.-C., Ip, W.-H., Kinoshito, D.,
Curves from the Palomar Transient Factory Survey; Rotation
150, Issue 3, article Id. 75, 35 pp.
137
ASTEROID LIGHTCURVE ANALYSIS AT
CS3-PALMER DIVIDE STATION:
2015 OCTOBER-DECEMBER
Brian D. Warner
Center for Solar System Studies – Palmer Divide Station
446 Sycamore Ave.
Eaton, CO 80615 USA
[email protected]
(Received: 2016 January 7 Revised: 2016 January 21)
Lightcurves for 14 main-belt asteroids were obtained at
the Center for Solar System Studies-Palmer Divide
Station (CS3-PDS) from 2015 October-December.
For the sake of brevity, only some of the previously reported
results may be referenced in the discussions on specific asteroids.
For a more complete listing, the reader is directed to the asteroid
lightcurve database (LCDB; Warner et al., 2009a). The on-line
version at http://www.minorplanet.info/lightcurvedatabase.html
allows direct queries that can be filtered a number of ways and the
results saved to a text file. A set of text files of the main LCDB
tables, including the references with bibcodes, is also available for
download. Readers are strongly encouraged to obtain, when
possible, the original references listed in the LCDB for their work.
16 Psyche. This well-studied outer main-belt asteroid was
observed to tie lightcurve features to those found, if any, with radar
and thermal observations made about the same. The period agrees
closely with previous results (see references in the LCDB).
CCD photometric observations of 14 main-belt asteroids were
made at the Center for Solar System Studies-Palmer Divide Station
(CS3-PDS) from 2015 October-December. Table I lists the
telescope/CCD camera combinations used for the observations. All
the cameras use CCD chips from the KAF blue-enhanced family
and so have essentially the same response. The pixel scales for the
combinations range from 1.24-1.60 arcsec/pixel.
Desig
Squirt
Borealis
Eclipticalis
Australius
Zephyr
Telescope
0.30-m f/6.3
0.35-m f/9.1
0.35-m f/9.1
0.35-m f/9.1
0.50-m f/8.1
Schmidt-Cass
Schmidt-Cass
Schmidt-Cass
Schmidt-Cass
R-C
Camera
ML-1001E
STL-1001E
ML-1001E
STL-1001E
FLI-1001E
Table I. List of CS3-PDS telescope/CCD camera combinations.
All lightcurve observations were unfiltered since even a clear filter
can result in a 0.1-0.3 magnitude loss. The exposure duration
varied depending on the asteroid’s brightness and sky motion.
Guiding on a field star sometimes resulted in a trailed image for
the asteroid.
Measurements were made using MPO Canopus. If necessary, an
elliptical aperture with the long axis parallel to the asteroid’s path
was used. The Comp Star Selector utility in MPO Canopus found
up to five comparison stars of near solar-color for differential
photometry. Catalog magnitudes were usually taken from the
MPOSC3 catalog, which is based on the 2MASS catalog
(http://www.ipac.caltech.edu/2mass)
but
with
magnitudes
converted from J-K to BVRI using formulae developed by Warner
(2007). The nightly zero points have been found to be consistent to
about ± 0.05 mag or better, but on occasion are as large as 0.1 mag.
This consistency is critical to analysis of long period and/or
tumbling asteroids. Period analysis is also done using MPO
Canopus, which implements the FALC algorithm developed by
Harris (Harris et al., 1989).
In the plots below, the “Reduced Magnitude” is Johnson V as
indicated in the Y-axis title. These are values that have been
converted from sky magnitudes to unity distance by applying
–5*log (rΔ) to the measured sky magnitudes with r and Δ being,
respectively, the Sun-asteroid and Earth-asteroid distances in AU.
The magnitudes were normalized to the given phase angle, e.g.,
alpha(6.5°), using G = 0.15, unless otherwise stated. The X-axis is
the rotational phase ranging from –0.05 to 1.05.
If the plot includes an amplitude, e.g., “Amp: 0.65”, this is the
amplitude of the Fourier model curve and not necessarily the
adopted amplitude for the lightcurve. The value is meant only to be
a quick guide.
4674 Pauling. This is a known binary (Merline et al., 2004) that
was discovered using adaptive optics. The satellite has an orbital
period of about 1200 hours and is too faint to be observed by
lightcurve photometry alone. The results agree with previous
results by the author (Warner, 2006; 2011) and others.
5087 Emel’yanov. The estimated diameter for this outer main-belt
asteroid is 13.3 km, assuming an albedo of pv = 0.057 and H =
13.1. It was in the same field as a planned NEA asteroid for two
nights, but only the first night provided sufficient coverage of a
bimodal lightcurve. A search of the half-periods of the likely full
period solutions led to adopting a final result of P = 14.5 ± 1.0 h
and amplitude A = 0.30 ± 0.03 mag. There were no previous
entries in the LCDB for the asteroid.
138
= 5.697 h. Observations in 2011 (Warner, 2011) changed that to P
= 3.321 h but with an alternate solution of P = 6.643 h. Skiff
(2011) found a similar pair of ambiguous solutions. The results
from the 2015 data seem to establish the shorter period with P =
3.2754 h since a fit to the longer period is not reasonable. The
2007 data were re-examined and found to fit P = 3.233 ± 0.002 h,
A = 0.05 mag.
9165 Raup. A Hungaria asteroid of about 5 km effective diameter,
Raup was observed for the second time by the author, the first time
being in 2014 (Warner, 2014). At that time, the period was
reported to be 560 h with the possibility of tumbling. The more
extended data set in 2015 nearly doubled the period, P = 1320 ±
10 h, and found a slightly larger amplitude of A = 1.34 ± 0.03 mag.
If the asteroid is tumbling, it would appear to be a very low level
since there were no outward signs in the 2015 lightcurve.
17447 Heindl. This is the first time that the author observed this
Hungaria as part of the on-going project to study this intriguing
group of asteroids (see Warner et al., 2009b). There were no
previous entries in the LCDB for Heindl.
(36496) 2000 QK49. This appears to be the first reported period
for 2000 QK49, an inner main-belt asteroid of about 2.8 km
effective diameter, assuming pv = 0.2, H = 15.1. It was in the same
field as a planned target on two successive nights. Fortunately,
each observing run covered more than a full cycle of the adopted
period, which resulted in a secure solution. There were no previous
entries in the LCDB.
20936 Nemrut Dagi. The author first worked this Hungaria as
(20936) 4835 T-1 (Warner, 2008). The period was reported to be P
139
(49669) 1999 RZ30. This asteroid was observed as part of the
Hungaria observing project (now more than 10 years old). This
appears to be the first reported period.
(53115) 1999 AM14. This middle main-belt asteroid was another
target of opportunity, meaning that it was in the same field as a
planned target. Only one night’s data were obtained, but the
proposed period of P = 4.0 ± 0.1 h seems a reasonable estimate.
There were no previous entries in the LCDB.
(135885) 2002 TX49. Another target of opportunity (in the same
field as 9165 Raup), 2002 TX49 is a middle main-belt asteroid of
about 2.6 km effective diameter, assuming pv = 0.1, H = 16.0.
Despite data from only one night, the amplitude and phase angle
make the period of P ~ 5.29 h more likely correct than not.
(139515) 2001 PD53. The Hungaria 9165 Raup was a target of
opportunity magnet in October. This was one of no less than four
such targets in the same field on one or more nights. 2001 PD53 is
an outer main-belt asteroid of about 4 km diameter. Given the
apparent coverage of more than half a cycle and amplitude, the
period of P = 8.3 ± 0.5 h seems to be reliable, though not fully
secure. There were no previous entries in the LCDB.
(241339) 2007 VL269. Another one of 9165 Raup’s entourage in
October was this 1.2 km inner main-belt asteroid. There were no
previous entries in the LCDB.
(241804) 2001 QW282. This is a 3 km outer main-belt asteroid
with no previous entries in the LCDB.
140
Number
16
4674
5087
9165
17447
20936
20936
36496
49669
53115
135885
139515
241339
241804
249590
Name
Psyche
Pauling
Emel'yanov
Raup
Heindl
4835 T-1
Nemrut Dagi
2000 QK49
1999 RZ30
1999 AM14
2002 TX49
2001 PD53
2007 VL269
2001 QW282
1996 UG2
2015 mm/dd
11/30-12/26
11/26-12/01
11/01-11/02
08/30-10/19
10/21-10/23
07
11/06-11/15
11/26-12/13
10/09-10/10
10/22-10/26
12/16-12/16
10/09-10/09
10/09-10/09
10/09-10/09
10/09-10/09
10/09-10/10
Pts
540
126
128
2907
181
161
467
146
132
62
49
77
74
71
87
Phase
4.5,4.1,7.5
31.5,31.7
11.8,12.1
23.2,3.3,11.8
3.6,3.2
27.4,30.2
27.2,22.6
13.1,12.5
15.7,17.2
4.0
3.9
3.3
4.6
15.6
11.1,10.6
LPAB
77
356
67
8
29
6
107
35
10
76
8
8
9
265
36
BPAB Period
P.E.
Amp
-4
4.1963 0.0005 0.13
15
2.532
0.002
0.13
-5
14.5
1
0.3
-7 1320
10
1.34
-5
2.569
0.005
0.18
-3
3.233
0.002
0.05
24
3.2754 0.0005 0.08
2
5.31
0.01
0.35
18
3.119
0.005
0.26
2
4.04
0.1
0.16
-3
5.3
0.5
0.33
-3
8.3
0.5
0.63
-3
7.7
0.5
0.85
-9
>12.
>0.2
2
4.45
0.05
0.23
A.E.
0.01
0.02
0.03
0.03
0.01
0.01
0.01
0.02
0.03
0.02
0.05
0.05
0.03
Group
MB-O
H
MB-O
H
H
H
H
MB-I
H
MB-M
MB-M
MB-O
MB-I
MB-O
MB-O
07
Table II. Observing circumstances. Observations in 2007. The phase angle (α) is given at the start and end of each date range, unless it
reached a minimum, which is then the second of three values. If a single value is given, the phase angle did not change significantly and the
average value is given. LPAB and BPAB are each the average phase angle bisector longitude and latitude, unless two values are given
(first/last date in range). The Group column gives the orbital group to which the asteroid belongs. The definitions and values are those used
in the LCDB (Warner et al., 2009a). H = Hungaria; MB-I/M/O = Main-belt inner/middle/outer.
The period shown in the lightcurve (7.0 ± 0.82 h) is just one of
many that fit the data. Assuming a bimodal lightcurve, the best
solution is an indefinite one of P ≥ 12 h and A ≥ 0.2 mag.
(249590) 1996 UG2. This was another target of opportunity. There
were no previous entries in the LCDB for the 3.5 km outer mainbelt asteroid. With data from two nights, the period is considered
mostly, but not completely, secure.
References
3, 24, 60, 261, and 863.” Icarus 77, 171-186.
Merline, W.J., Tamblyn, P.M., Dumas, C., Menard, F., Close,
L.M., Chapman, C.R., Duvert, G., Ageroges, N. (2004). “S/2004
(4674) 1. IAUC 8297.
Skiff, B.A. (2011) Posting on CALL web site.
http://www.minorplanet.info/call.html
Warner, B.D., Pravec, P., Kusnirak, P., Foote, C., Foote J., Galad,
A., Gajdos, S., Kornos, L., Vilagi, J., Higgins, D., Nudds, S.,
Kugly, Y.N., Gaftonyuk, N.M. (2006). “Lightcurves analysis for
Hungaria asteroids 3854 George, 4440 Tchantches and 4674
Pauling.” Minor Planet Bull. 33, 34-35.
Divide Observatory: September-December 2007.” Minor Planet
Bull. 35, 67-71.
Warner, B.D., Harris, A.W., Pravec, P. (2009a). “The Asteroid
Acknowledgements
Funding for PDS observations, analysis, and publication was
provided by NASA grant NNX13AP56G. Work on the asteroid
lightcurve database (LCDB) was also funded in part by National
Science Foundation grants AST-1210099 and AST-1507535.
This research was made possible in part based on data from
CMC15 Data Access Service at CAB (INTA-CSIC) and the
AAVSO Photometric All-Sky Survey (APASS), funded by the
Robert Martin Ayers Sciences Fund. (http://svo2.cab.intacsic.es/vocats/cmc15/).
This publication makes use of data products from the Two Micron
All Sky Survey, which is a joint project of the University of
Massachusetts and the Infrared Processing and Analysis
Center/California Institute of Technology, funded by the National
Aeronautics and Space Administration and the National Science
Foundation. (http://www.ipac.caltech.edu/2mass/)
Warner, B.D., Harris, A.W., Vokrouhlický, D., Nesvorný, D.,
Bottke, W.F. (2009b). “Analysis of the Hungaria asteroid
population.” Icarus 204, 172-182.
Warner, B.D (2011a). “Lightcurve Analysis at the Palmer Divide
Observatory: 2010 June-September.” Minor Planet Bull. 38, 25-31.
Warner, B.D. (2011b). “Asteroid Lightcurve Analysis at the
Palmer Divide Observatory: 2010 December- 2011 March.” Minor
Warner, B.D. (2014). “Asteroid Lightcurve Analysis at CS3Palmer Divide Station: 2014 January-March.” Minor Planet Bull.
41, 144-155.
141
LIGHTCURVE ANALYSIS AND ROTATION PERIOD
DETERMINATION FOR ASTEROID 11268 SPASSKY
Dr. Melissa N. Hayes-Gehrke, Ryan Brink, Sean Brody,
Danielle Daitch, Dimitri Deychakiwsky, Robert Huang,
Sam Leitess, John Carlo Mandapat, Christine Schroeder
College Park, MD 20742-2421 USA
[email protected]
Dr. Daniel A. Klinglesmith III
Socorro, NM USA
Acknowledgements
Funding for observations was provided by the Astronomy
Department at University of Maryland. We would also like to
thank itelescope.net for the use of their facilities to study this
asteroid. The Etscorn Campus Observatory operations are
supported by the Research and Economic Development Office of
New Mexico Institute of Mining and Technology (NMIMT).
References
ECO (2015). Etscorn Campus Observatory.
http://www.mro.nmt.edu/education-outreach/etscorn-campusobservatory
Photometric observations of main-belt asteroid 11268
Spassky were made over four nights during 2015
October and November. The observations were obtained
remotely at the iTelescope Observatory in Nerpio, Spain,
as well at the Etscorn Campus Observatory in New
Mexico. Analysis of the data found a rotation period of
5.645 ± 0.003 h.
Observations of the asteroid 11268 Spassky were obtained on 2015
Oct 21 and Nov 3 and 5 using the T7 Planewave 0.43-m CDK
telescope at the Nerpio, Spain, AstroCamp Observatory. The
telescope uses an SBIG STL-11000M CCD with 9x9 µm pixels
which give a resolution 0.63 arcsec/pixel. Of the 61 images taken
using 300-s exposure times, a luminance filter, and at 1x1 binning,
two were discarded due to blurriness and saturation.
On 2015 Nov 14, 63 images were obtained by Dr. Daniel
Klinglesmith of the Etscorn Campus Observatory (ECO, 2015) in
New Mexico. His observations were obtained with a Celestron
0.35-m Schmidt-Cassegrain (SCT) telescope on a Software Bisque
Parmount ME mount (http://www.bisque.com/sc/) and SBIG STL1001E CCD. After collaborating with Dr. Klinglesmith, a total of
122 images were used in data analysis and creation of the
lightcurve.
Analysis of the data was performed using MPO Canopus (Warner,
2013). Images from the various nights of observation were
uploaded into MPO Canopus where aperture and differential
photometry along with a Fourier series analysis routine (Harris et.
al., 1989) were employed to compute a phased lightcurve for the
asteroid.
The best-fit period of 5.645 ± 0.003 h clearly had the lowest RMS
fit, yielding no other plausible matches. The amplitude of the
lightcurve is 0.62 mag. This result fits within the average statistics
that have been collected for main-belt asteroids.
24, 60, 261, and 863.” Icarus 77, 171-186.
Warner, B.D. (2013). MPO Software. MPO Canopus version
LIGHTCURVE ANALYSIS OF THE
NEAR-EARTH ASTEROID 2015 TB145
Brian D. Warner
Center for Solar System Studies–Palmer Divide Station
446 Sycamore Ave.
Eaton, CO 80615 USA
[email protected]
Albino Carbognani
Astronomical Observatory
of the Aosta Valley Autonomous Region (OAVdA)
Lignan 39, 11020 Nus (Aosta), ITALY
Lorenzo Franco
Balzaretto Observatory (A81), Rome, ITALY
Julian Oey
Blue Mountains Observatory (MPC Q68)
Leura, NSW, AUSTRALIA
The near-Earth asteroid 2015 TB145 made a fly-by of
Earth in 2015 October. We observed the NEA in support
of radar observations planned for late October. Our data
set of more than 1200 data points obtained from October
19-31 led to a solution of P = 2.938 ± 0.002 h and
A = 0.13 ± 0.02 mag.
The near-Earth asteroid (NEA) TB145 made a fly-by of Earth on
2015 October 31 (~0.003 AU). We responded to a request from the
radar team for photometry prior to the fly-by in order to help plan
their observations. Tables I and II give the equipment used and the
dates of observations for each observer.
We began observations at CS3-PDS with the 0.5-m telescope on
October 19, when the asteroid was V ~ 18.7 but the sky motion
was negligible and so exposures could be long enough (240 s) to
142
get a reasonable SNR. By the end of the month, Franco was using
exposures of only 10 sec as the sky motion approached 900”/min.
OBS
Warner
Carbognani
Franco
Oey
Telescope
0.30-m
0.50-m
0.81-m
0.20-m
0.35-m
0.61-m
Camera
f/9.6
f/8.1
f/7.9
f/5.5
f/5.9
f/6.8
SCT
R-C
R-C
SCT
SCT
CDK
FLI ML-1001E
FLI PL-1001E
FLI PL-1001E
ST-7XME
ST-8XME
Apogee U42
Table I. List of observers and equipment.
Obs
Warner
Carbognani
Franco
Oey
2015 Oct
Sess
19-24
26-27
30
24
1-4,6
9-10
12-18
5
31
20-30
24,29,30
7-8
11,19
α
LPAB
BPAB
33.8
34.7
46
54
-14
-8
33.9
36.4
37.4
33.9
34.8
48
-13
-13
-8
-13
-11
48-54
48-51
Table II. Dates of observation for each observer. α is the solar
phase angle at the earliest and latest observation. The last two
columns are the average or extreme phase angle bisector longitude
and latitude (see Harris et al., 1984).
One of the concerns for a small asteroid is that the rotation period
might be very fast, on the order of only a few minutes. To avoid
so-called rotational smearing, exposures must be no longer than
about 0.19 the rotation period of the asteroid (see Pravec et al.,
2000). In this case, the estimated size made it unlikely that the
period would be less than about 2 hours, and so the long exposures
at the start of the campaign would not be a problem.
All observations were unfiltered. The CS3-PDS observations were
referenced to V magnitudes from the MPOSC3 catalog, which is
based on the 2MASS catalog converted to the BVRcIc system
using formulae developed by Warner (2007). The other
observations were referenced mostly to R magnitudes taken either
from the MPOSC or UCAC3 catalogs.
All images were measured in MPO Canopus and the data files sent
to Warner for period analysis, again using MPO Canopus, which
incorporates the FALC Fourier analysis algorithm developed by
Harris (Harris et al., 1989). Somewhat arbitrary zero point offsets,
for the R magnitudes in particular, were required to find a solution
with the minimum RMS deviation that also produced a total
lightcurve similar to the individual parts.
Acknowledgements
Funding for Warner was provided by NASA grant NNX13AP56G.
Research at the Astronomical Observatory of the Aosta Valley
Autonomous Region was supported by a 2013 Shoemaker NEO
Grant. The Apogee U 42 camera at Blue Mountains Observatory
was kindly provided by the 2015 Shoemaker NEO Grant of the
Planetary Society.
References
444 Gyptis.” Icarus 57, 251-258.
H., Zeigler, K.W., (1989). “Photoelectric Observations of
Asteroids 3, 24, 60, 261, and 863.” Icarus 77, 171-186.
Pravec, P., Hergenrother, C., Whiteley, R., Sarounova, L.,
Kusnirak, P. (2000). “Fast Rotating Asteroids 1999 TY2, 1999
SF10, and 1998 WB2.” Icarus 147, 477-486.
Warner, B.D. (2007). “Initial Results of a Dedicated H-G
Program.” Minor Planet Bul. 34, 113-119.
CALL FOR OBSERVATIONS
Frederick Pilcher
Las Cruces, NM 88011 USA
[email protected]
The combined data set used 1244 data points for the analysis,
which found a solution of P = 2.938 ± 0.002 h and A = 0.13 ± 0.02
mag.
Quite often during a close fly-by, the viewing aspect (phase angle
bisector (PAB); see Harris et al., 1984) and/or phase angle change
significantly. Either one can cause a noticeable change in the
synodic period and/or amplitude over a span of a few weeks, if not
days. In this case, neither the PAB or phase angle changed much
during the two-week span of observations. Within the limits of the
individual data sets, we did not see a noticeable change in either
the period or amplitude of the lightcurve.
Observers who have made visual, photographic, or CCD
measurements of positions of minor planets in calendar 2015 are
encouraged to report them to this author on or before 2016 April 1.
This will be the deadline for receipt of reports which can be
included in the “General Report of Position Observations for
2015,” to be published in MPB Vol. 43, No. 3.
143
NEAR-EARTH ASTEROID LIGHTCURVE ANALYSIS
AT CS3-PALMER DIVIDE STATION:
2015 OCTOBER–DECEMBER
Brian D. Warner
Center for Solar System Studies / MoreData!
446 Sycamore Ave.
Eaton, CO 80615 USA
[email protected]
Lightcurves for 36 near-Earth asteroids (NEAs) were
obtained at the Center for Solar System Studies-Palmer
Divide Station (CS3-PDS) from 2015 OctoberDecember.
CCD photometric observations of 36 near-Earth asteroids (NEAs)
were made at the Center for Solar System Studies-Palmer Divide
Station (CS3-PDS) from 2015 October-December. Table I lists the
telescope/CCD camera combinations used for the observations. All
the cameras use CCD chips from the KAF blue-enhanced family
and so have essentially the same response. The pixel scales for the
combinations range from 1.24-1.60 arcsec/pixel.
Desig
Squirt
Borealis
Eclipticalis
Australius
Zephyr
Telescope
0.30-m f/6.3
0.35-m f/9.1
0.35-m f/9.1
0.35-m f/9.1
0.50-m f/8.1
Schmidt-Cass
Schmidt-Cass
Schmidt-Cass
Schmidt-Cass
R-C
lightcurve database (LCDB; Warner et al., 2009). The on-line
version at http://www.minorplanet.info/lightcurvedatabase.html
allows direct queries that can be filtered a number of ways and the
results saved to a text file. A set of text files of the main LCDB
tables, including the references with bibcodes, is also available for
download. Readers are strongly encouraged to obtain, when
possible, the original references listed in the LCDB for their work.
If the plot includes an amplitude, e.g., “Amp: 0.65”, this is the
amplitude of the Fourier model curve and not necessarily the
adopted amplitude for the lightcurve. The value is provided as a
matter of convenience.
1620 Geographos. The period and shape of this asteroid have been
studied in detail (e.g., Hudson and Ostro, 1999; Higgins et al.,
2008). The results from the CS3-PDS observations agree well with
those earlier findings. The 2015 apparition featured about the
minimum lightcurve amplitude previously seen. In some years, the
amplitude has been nearly double: 2.03 mag.
Camera
ML-1001E
STL-1001E
ML-1001E
STL-1001E
FLI-1001E
Table I. List of CS3-PDS telescope/CCD camera combinations.
All lightcurve observations were unfiltered since a clear filter can
result in a 0.1-0.3 magnitude loss. The exposure duration varied
depending on the asteroid’s brightness and sky motion. Guiding on
a field star sometimes resulted in a trailed image for the asteroid.
Measurements were done using MPO Canopus. If necessary, an
elliptical aperture with the long axis parallel to the asteroid’s path
was used. The Comp Star Selector utility in MPO Canopus found
up to five comparison stars of near solar-color for differential
photometry. Catalog magnitudes were usually taken from the
MPOSC3 catalog, which is based on the 2MASS catalog
(http://www.ipac.caltech.edu/2mass)
but
with
magnitudes
converted from J-K to BVRI using formulae developed by Warner
(2007). The nightly zero points have been found to be consistent to
about ± 0.05 mag or better, but on occasion are as large as 0.1 mag.
Period analysis is also done using MPO Canopus, which
implements the FALC algorithm developed by Harris (Harris et
al., 1989).
In the plots below, the “Reduced Magnitude” is Johnson V as
indicated in the Y-axis title. These are values that have been
converted from sky magnitudes to unity distance by applying
–5*log (rΔ) to the measured sky magnitudes with r and Δ being,
respectively, the Sun-asteroid and Earth-asteroid distances in AU.
The magnitudes were normalized to the given phase angle, e.g.,
alpha(6.5°), using G = 0.15, unless otherwise stated. The X-axis is
the rotational phase, ranging from –0.05 to 1.05.
For the sake of brevity, only some of the previously reported
results may be referenced in the discussions on specific asteroids.
For a more complete listing, the reader is directed to the asteroid
(5646) 1990 TR. This was the second time the author observed
1990 TR, the first being in 2012 (Warner, 2013) when the
amplitude was only 0.12 mag. The 0.32 mag amplitude in 2015
would seem to indicate the asteroid presented a more equatorial
view. The periods from the two apparitions are in good agreement.
(6611) 1993 VW. Pravec et al. (2005web) reported the possibility
that this NEA is a binary, finding a primary period of 2.5568 h and
a secondary period of 17.19 h. No mutual events were seen that
would have firmly confirmed the existence of a satellite. Analysis
of the CS3-PDS data only added to the mystery. Two possible
solutions evolved, one involving two periods, P1 = 3.40 ± 0.01 h
144
and P2 = 9.34 ± 0.01 h, and the other a single period solution of PS
= 6.831 ± 0.001 h. It’s worth noting that P1 is almost exactly 1/2PS.
All attempts to fit the CS3 data to the periods found by Pravec et
al. were unsatisfactory.
(33342) 1998 WT24. The period and shape of this NEA were welldetermined by Busch et al. (2008) using radar observations. The
2015 apparition presented a good opportunity to study the
evolution of the lightcurve over a three-week span.
(11054) 1991 FA. Pravec et al. (2001web) reported a solution of
P = 2.57223 h, A = 0.08 mag, but no lightcurve is available. Their
data set spanned almost two months starting in 2001 November. A
period search using the CS3 data, which consisted of three
consecutive nights, found a strong solution at 2.926 h and a
ntoably weaker one at about 2.6 h. The CS3 were forced to fit a
period in the range of 2.5-2.7 h, which found P = 2.615 h, A = 0.14
mag. However, that solution is not as good a fit.
Mid-date
Phase
PABL
PABB
Nov
Nov
Dec
Dec
Dec
69.8
63.8
49.8
42.5
23.5
97.6
97.1
93.3
90.3
70.6
-15.6
-15.3
-14.8
-14.4
-9.7
23
27
03
05
11
Table II. Observing circumstances during the 2015 apparition. The
Mid-date is approximate middle of each data set. The phase and
phase angle bisector were computed for 0 UT for that date.
145
The “All” plot shows what happens when trying to merge data sets
with significantly different amplitudes and synodic periods, the
latter especially if the total span of the observations covers a large
number of rotations. The plots A-E show the evolution of the shape
and amplitude of the lightcurve as the phase angle decreased.
Overall, the synodic period increased by about 0.01 h from the first
observations to the last while the asteroid phase angle decreased to
towards 0°. This is usually an indication of retrograde rotation, i.e.,
a pole latitude λ < 0. The latitude found by Busch et al. (2008) was
λ = –22°
(53426) 1999 SL5. This appears to be the first reported period for
this NEA. The solution is reliable for rotational studies but not
fully secure. The next good opportunity for follow-up is 2023
August when it will again be at +59° and V ~ 17.6.
146
(88263) 2001 KQ1. No previous entries were found in the LCDB
for 2001 KO1. The large amplitude and lightcurve asymmetry
virtually assure that the bimodal solution is correct (see Harris et
al., 2014).
(112985) 2002 RS28. Three different data sets from 2015 gave
three different results. The first two (Warner, 2015; 2016) gave
ambiguous results. Despite a 0.24 mag amplitude in 2015 July, the
data led to three equally-likely solutions, one close the one found
using the 2015 November data. The asteroid doesn’t get brighter
than V = 17.0 again until 2025.
(137084) 1998 XS16. Pravec et al. (1999web) found a period of
5.4211 h. The solution here is in good agreement.
(138852) 2000 WN10. The periods found by Pravec et al.
(2011web), Skiff et al. (2012), and from the CS3 data are in good
agreement.
(152679) 1998 KU2. No single period could be found, though one
of about 125 h roughly fits a bimodal lightcurve. It’s very likely
this asteroid is in a tumbling state (non-principal axis rotation,
NAPR). See Pravec et al. (2014; 2005a).
(152978) 2000 GJ147. This appears to be the first reported period
for this NEA. Despite the noisy data, the amplitude and low phase
angle made the bimodal solution almost certain. The next time the
asteroid is brighter than V = 18.0 is 2020 November.
147
(155110) 2005 TB. There were no previous entries in the LCDB
for 2005 TB. The solution is considered secure. The next
apparition brighter than V = 18.0 is 2025 November, at –62°.
(155334) 2006 DZ169. This NEA was observed at CS3 in 2015
August (Warner, 2016) when the amplitude was 0.21 mag. The
amplitude decreased to 0.17 mag for the October observations.
This was expected since the phase angle dropped from 42° to 10°
and lightcurve amplitude is known to decrease with phase angle
(Zappala et al., 1990).
(163899) 2003 SD220. There are very slight hints that this asteroid
is tumbling (the slopes of some sessions doesn’t quite match the
model curve slope). Tumbling would not be unexpected since the
approximate damping time to single axis rotation is greater than
the age of the Solar System (see Pravec et al., 2014).
(194268) 2001 UY4. There were no previous entries in the LCDB
to help guide the period analysis. As the period spectrum shows,
there are several likely solutions, the favored one being 5.91 h.
Another solution, at 7.88 h, may be a fit by exclusion, where the
Fourier modeling finds a lower RMS by minimizing the number of
overlapping data points in the solution. Such a solution is often
indicated when there is a significant gap in the lightcurve. It’s
worth noting that the two periods have an integral ratio of 4:3.
(159399) 1998 UL1. This appears to be the first reported
lightcurve for 1998 UL1. While no other solutions were of nearly
equal fit to the Fourier model, this period should not be considered
definitive.
148
(241596) 1998 XM2. The interesting shape of the lightcurve for
1998 XM2 may indicate a concavity at one end of an elongated
body. Those interested in follow-up will have to wait until 2027
May for it to be V < 18.0 again.
On the other hand, when plotting the half periods of both solutions,
the best fit came at 3.94 h, which would favor the 7.88 h solution,
assuming a bimodal lightcurve. However, this may not be a good
assumption given the low amplitude and phase angle (see Harris et
al., 2014).
(194386) 2001 VG5. The period for 2001 VG5 has been reported
twice before: Polishook (2009; 6.6 h) and Koehn et al. (2014;
6.351 h). The results based on the CS3 data are in good agreement
with Koehn et al.
(200754) 2001 WA25. There were no previous entries in the
LCDB for this asteroid. The result is considered almost secure. The
large scatter in relation to the amplitude leaves the period a little in
doubt, but mostly out of a sense of caution.
(253106) 2002 UR3. It’s very possible that 2002 UR3 is a tumbler.
Attempts to find a more bimodal than trimodal solution were
unsuccessful. The period is much longer than expected for a
damping time equal to the age of the Solar System, making
tumbling maybe more likely than not. The 2015 apparition at
V = 15.6 was brighter than most. It “blazes” through the sky in
2028 when it reaches V = 14.3 at +62° declination.
(294739) 2008 CM. This NEA became the subject of intense and
detailed radar observations in late 2015. Optical observations were
hampered by very fast sky motion and a nearly full moon at the
149
time of closest approach. The asteroid was observed before
(Warner, 2014) when a secure result of P = 3.054 h, A = 0.48 mag
was found.
refocusing routine about every hour. This process took anywhere
from 3-8 minutes. It appears that these breaks were almost synced
to the rotation period and so occurred at the same places in the
curve throughout each run. That is one explanation.
Another might be that scattered light from a nearly full moon being
30-40° away on the two runs created a gradient across the image
and so, as the comp stars moved from right to left, the base
differential magnitude would change and then reset when a new set
of comparison stars was used. To check on this, two tests were run.
The first was to remeasure the images and always use comparison
stars on the right side of the image and, if possible, the middle half
vertically. This would avoid at least half any gradient change. This
did not make a difference. The shifts still occurred at the focusing
breaks and the amplitude remained at about 0.4 mag.
The second test was to find the pixel values in a random sampling
of images processed with master flat-fields and darks. For each
image, the stars were removed leaving (almost) only sky
background pixels. The image was then divided into 64 columns
that were 16-pixels wide and 1024 pixels high. The average pixel
value of the subregions of 16384 pixels was found and then plotted
versus starting column, a sample of which is shown here.
The plot shows a nearly flat response from the left to right side of
the image. The standard deviation of the mean of the column
averages was 0.2%, or about 0.002 mag. A similar check was done
dividing the images into 16-pixel high rows, to see if there was a
gradient from top to bottom. The standard deviation was half that
for the columns average.
The lightcurves for 2015 Dec 27 and 28 differ in both amplitude
and synodic period, with the latter having the shorter period and
smaller amplitude. This follows since the phase angle was about
8-10° less on the second day (see Zappala et al., 1990). The
combined lightcurve (“All”) gives an average period and amplitude
but does not fit the data as well as the individual curves.
The most noticeable feature is the very sharp decline at about 0.45
and 0.95 rotation phase. It’s believed that this is the result in bad
timing. During both observing runs, which used exposures of only
10 seconds with a 15-second pause between images and
repositioned the telescope every 20 images, the script also forced a
Imaging when there the moon is in the sky can be problematic if
the telescope is not well baffled throughout the optical path.
However, waiting until the dark of the moon is not always an
option. In fact, it often is not. Despite the tests run in this case, the
unusual behavior of the lightcurves may have been due to
moonlight or other systematic issues other than bad timing. It is
worth noting that only one other time has such a problem been
seen at CS3 with a fast-moving object where obvious systematic
issues could be eliminated. There again, the shifts in the lightcurve
were nearly in sync with the breaks for focusing runs.
This highlights the need when working objects with relatively
short periods, i.e., P < 3 hours, to vary the imaging cadence as
much as possible. This means not only random intervals between
individual images but, as this case may show, also random
intervals between repositioning or refocusing the telescope.
(442243) 2011 MD11. There were no previous entries in the
LCDB for 2011 MD11. The period makes it a potential binary
asteroid candidate. The next good follow-up opportunity comes in
2019 October at V ~ 17.7, Dec +26°.
150
(443837) 2000 TJ1. While there were no previous lightcurve
results in the LCDB, it did include an entry from Thomas et al.
(2014), who reported that the asteroid is of taxonomic type Sq
based on warm-Spitzer IR observations. The next photometry
opportunity comes in 2020 October when the asteroid will be
V ~ 16.9 at +5° declination.
Assuming the second period is valid, it might represent a fully
asynchronous satellite, i.e., one where the rotation period is not
also the orbital period. The next chance for confirmation by radar
or optical observations isn’t until 2024 October, when the asteroid
will reach a minimum distance of 0.06 AU, V ~ 14.1, Dec +19°.
(452302) 1995 YR1. This appears to be the first reported
lightcurve period for this NEA. The period is considered nearly
secure, the small issues being the low SNR and the fact that most
observing runs covered less than half a cycle.
(450649) 2006 UY64. There were no previous entries in the LCDB
for 2006 UY64. A single period solution did not quite fit the data.
A dual period analysis in MPO Canopus found two periods: P1 =
2.824 ± 0.002 h, A1 = 0.09 ± 0.01 mag and P2 = 4.800 ± 0.005 h,
A2 = 0.05 ± 0.01 mag. The shorter period makes the asteroid a
good binary candidate.
2007 EA26. This appears to be the first reported period for 2007
EA26, an NEA with an estimated diameter of 200 meters.
2009 TK. There were no previous entries in the LCDB for 2009
TK. The estimated size of only 100 meters made it possible that
151
this was a superfast rotator, P < 2 h, and so exposures were kept to
30 seconds. Based on Pravec et al. (2000), this would avoid
rotational smearing as long as the period was about 3 minutes or
longer. The short exposures led to a higher than preferred SNR, but
proved to be the right choice given the rotation period of just over
6 minutes.
The lightcurve shape is unusual but this may be due in part to the
somewhat high phase angle. The double period, P ~ 0.216 h was
tested. This produced a highly symmetrical lightcurve with both
halves matching the one in the plot and was rejected.
2015 SZ. There were no previous entries in the LCDB for 2015
SZ. While there were no outward signs of the asteroid being a
tumbler, it would not be unexpected since the period for a damping
time of 4.5 Gy is only 9 hours (see Pravec et al., 2014 and
references therein). It’s possible that the low SNR data masked
small-level tumbling.
Unfortunately, this will be the best result for this NEA for some
time. It does not get brighter than V ~ 21 nor will it be within reach
of existing radar facilities through 2050.
2011 WN15. There were no previous entries in the LCDB for 2011
WN15. The period of just less than 2.1 hours, the so-called “spin
barrier” between rubble pile and strength-bound asteroids. This
should not be considered overly significant. This asteroid could
easily be a rubble pile with sufficient bonding forces to allow it to
spin a little faster than might be expected possible. The spin barrier
is not a hard-fast but “fuzzy line” at best and depends on any
number of factors.
Here is another case where the large scatter in the data was
overcome by having a large number of data points in observing
runs that each covered a significant part of a cycle.
2015 XC. This NEA proved to be a tumbler (Petr Pravec, private
communications). The “Float” plot is the best fit solution using the
full data set when searching for a single period in MPO Canopus.
2011 YS62. There were no previous entries in the LCDB for this
NEA. The period is considered secure due to the amplitude and
asymmetrical shape of the lightcurve.
152
2015 WF13. There were no previous entries in the LCDB for 2015
WF13, and likely won’t be any more (lightcurves at least) for some
time. The NEA won’t get brighter than V ~ 23.6 through 2050.
Fortunately, the amplitude of the lightcurve was sufficient to
overcome the low SNR data and allow finding a secure period. The
estimated diameter is only 60 meters, and so the superfast period of
only 12.7 minutes was not unexpected. Because of its small size,
exposures were limited to 30 seconds to avoid rotational smearing
(see Pravec et al., 2000).
2015 TA25. A limited data set and apparently somewhat long
period conspired against finding a reliable solution for 2015 TA25.
The period spectrum shows several equally possible solutions. The
period of 15.53 h is adopted here based on fitting the data to halfperiods and the best fit being near 7.8 hours. There were no
previous entries in the LCDB.
This is very reminiscent of a plot in Harris et al. (2014) which was
used to demonstrate how a “beat period” could be found for a
tumbler with similar periods of rotation and precession. The
amplitude of 0.64 mag precludes a complex shape (Harris et al.,
2014), adding further evidence for the asteroid being in a tumbling
state. Pravec found periods of P1 = 0.181099 h and P2 =
0.27998 h. However, these are not unique and other periods are
possible, especially for P2. The P1 and P2 plots have been forced
to these two periods for comparison purposes only.
2015 SV2. Here is another long-period NEA that might be
expected to show signs of tumbling but does not, at least that can
be seen with the existing data set. There were no previous entries
in the LCDB. The 2015 apparition was the last one through 2050
where the asteroid will be brighter than V ~ 20.
153
Number
1620
5646
6611
11054
33342
53426
88263
112985
137084
138852
152679
152978
155110
155334
159399
163899
194268
194386
200754
241596
253106
294739
294739
442243
443837
450649
452302
Name
Geographos
1990 TR
1993 VW
1991 FA
1998 WT24
1999 SL5
2001 KQ1
2002 RS28
1998 XS16
2000 WN10
1998 KU2
2000 GJ147
2005 TB
2006 DZ169
1998 UL1
2003 SD220
2001 UY4
2001 VG5
2001 WA25
1998 XM2
2002 UR3
2008 CM
2008 CM
2011 MD11
2000 TJ11
2006 UY64
1995 YR1
2007 EA26
2009 TK
2011 WN15
2011 YS62
2015 SZ
2015 XC
2015 SV2
2015 WF13
2015 TA25
2015 XU378
2015 mm/dd
12/13-12/16
11/18-11/24
10/11-11/15
10/09-10/11
11/22-12/12
10/12-10/19
10/11-10/29
11/05-11/15
10/11-10/14
11/19-11/21
10/24-11/11
11/23-11/30
10/27-10/30
10/19-10/23
10/11-10/14
11/06-11/28
10/31-11/03
12/01-12/03
12/04-12/05
10/07-10/10
11/12-11/23
12/27-12/27
12/28-12/28
10/05-10/08
10/03-10/08
10/31-11/03
12/13-12/17
10/30-11/15
10/07-10/07
12/05-12/12
12/01-12/04
10/04-10/09
12/06-12/07
12/02-12/18
12/04-12/05
11/05-11/07
12/17-12/18
Pts
186
112
340
88
1400
122
202
417
123
242
1291
279
205
137
166
740
400
155
104
167
1650
982
499
102
496
536
301
548
433
820
462
816
244
1004
361
335
562
Phase
26.9,28.0
50.1,49.0
8.5,6.9,21.4
57.4,58.0
70.4,21.7,32.5
36.1,32.3
38.1,35.6
47.6,44.9
71.7,68.6
24.8,23.9
30.2,13.6
4.3,14.3
21.7,19.7
9.0,11.6
13.0,11.2
82.0,80.7,81.9
28.2,21.5
1.5,3.3
45.5,44.3
53.1,52.1
4.9,4.1,22.6
52.9,52.9
45.3,45.3
12.9,13.1
3.9,2.8,11.8
44.2,49.7
34.5,40.0
22.0,43.6
27.7,27.7
63.3,18.2
40.0,43.4
17.7,30.5
30.5,46.9
37.2,20.4
51.3,47.7
7.8,12.1
59.5,59.7
A
LPAB
51
146
27
66
90
9
68
321
18
46
62
60
31
15
28
100
47
67
109
13
76
120
119
4
11
14
107
37
26
95
53
27
58
85
46
39
59
BPAB
21
3
5
6
-14
32
4
20
61
-11
-4
6
17
1
14
21
-16
0
8
49
-1
16
10
-5
-4
13
-5
20
-8
9
19
0
12
15
-2
6
-1
P
Period
5.223
3.203
2.63
2.926
3.697
5.03
13.16
4.787
5.419
4.463
T
125
13.22
3.479
4.68
4.01
285
7.88
6.38
3.653
8.75
180
3.041
2.966
2.43
14.09
2.824
5.006
65.0
0.10794
1.948
17.53
41
T
0.181099
43.91
0.21194
A
15.53
3.021
P.E.
0.005
0.002
0.01
0.005
0.001
0.05
0.01
0.005
0.005
0.005
5
0.05
0.005
0.02
0.02
5
0.02
0.01
0.005
0.02
5
0.004
0.004
0.002
0.03
0.002
0.005
0.2
0.00005
0.001
0.05
1
0.000006
0.05
0.00005
0.05
0.005
Amp
1.02
0.26
0.05
0.15
0.29
0.15
0.52
0.09
1.18
0.38
1.35
0.47
0.43
0.17
0.12
2.2
0.13
0.4
0.31
0.4
0.36
0.44
0.49
0.15
0.49
0.09
0.23
0.56
0.28
0.15
0.42
1.33
0.55
0.8
0.23
0.35
0.3
A.E.
0.03
0.03
0.02
0.02
0.03
0.03
0.03
0.02
0.03
0.03
0.20
0.05
0.03
0.03
0.03
0.1
0.02
0.03
0.04
0.03
0.03
0.02
0.02
0.01
0.04
0.02
0.03
0.05
0.04
0.03
0.03
0.10
0.05
0.03
0.05
0.05
0.04
Grp
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
NEA
T
Table III. Observing circumstances. preferred period for an ambiguous solution. period of primary in binary. dominant period of a tumbler.
Pts is the number of data points used in the analysis. The phase angle (α) is given at the start and end of each date range, unless it
reached a minimum, which is then the second of three values. If a single value is given, the phase angle did not change significantly and the
average value is given. LPAB and BPAB are, respectively the average phase angle bisector longitude and latitude, unless two values are given
(first/last date in range). Grp is the orbital group of the asteroid. See Warner et al. (LCDB; 2009; Icarus 202, 134-146.).
2015 XU378. This appears to be the first reported lightcurve for
2015 XU378. The period seems secure, which is fortunate since
the asteroid won’t be brighter than V ~ 22 mag through 2050.
Science Foundation grants AST-1210099 and AST-1507535.
This research was made possible in part based on data from
CMC15 Data Access Service at CAB (INTA-CSIC) and the
AAVSO Photometric All-Sky Survey (APASS), funded by the
Robert Martin Ayers Sciences Fund. (http://svo2.cab.intacsic.es/vocats/cmc15/).
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M.C., Hine, A.A. (2008). “Physical properties of near-Earth
Asteroid (33342) 1998 WT24.” Icarus 195, 614-621.
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PHOTOMETRY CAMPAIGN
Pedro V. Sada
Departamento de Física y Matemáticas
Universidad de Monterrey
Av. I. Morones Prieto 4500 Pte.
Garza García, N.L., 66238
MÉXICO
[email protected]
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Pravec, P., Wolf, M., Sarounova, L. (1999web, 2001web,
2005web, 2011web). http://www.asu.cas.cz/~ppravec/neo.htm
Skiff, B.A., Bowell, E., Koehn, B.W., Sanborn, J.J., McLelland,
K.P., Warner, B.D. (2012a). “Lowell Observatory Near-Earth
Asteroid Photometric Survey (NEAPS) - 2008 May through 2008
December.” Minor Planet Bull. 39, 111-130.
Thomas, C.A., Emery, J.P., Trilling, D.E., Delbo, M., Hora, J.L.,
Mueller, M. (2014). “Physical characterization of Warm Spitzerobserved near-Earth objects.” Icarus 228, 217-246.
Program.” Minor Planet Bull. 34, 113-119.
Lightcurve Database.” Icarus 202, 134-146. Last update: 2015
Dec. http://www.minorplanet.info/lightcurvedatabase.html
Samuel Navarro-Meza & Mauricio Reyes-Ruiz
Instituto de Astronomía
Universidad Nacional Autónoma de México
Ensenada, Baja California, MÉXICO
Lorenzo L. Olguín, Julio C. Saucedo & Pablo Loera-González
Depto. de Investigación en Física
Universidad de Sonora
Hermosillo, MÉXICO
The 2015 Mexican Asteroid Photometry Campaign was
organized at the 2nd National Planetary Astrophysics
Workshop held in 2015 March at the Universidad
Autónoma de Nuevo León in Monterrey, México. Three
asteroids were selected for coordinated observations
from several Mexican observatories. We report full
lightcurves for the main-belt asteroid 1084 Tamariwa (P
= 6.195 ± 0.001 h) and near-Earth asteroid (NEA) 4055
Magellan (P = 7.479 ± 0.001 h). Asteroid 1466
Mundleria was also observed on eight nights but no
lightcurve was obtained because of its faintness, a
crowded field-of-view, and low amplitude (<0.03 mag).
Planetary astronomy in general is becoming a more popular field
of scientific study in Mexico, in part due to the recent
establishment
of
the
Mexican
Space
Agency
(http://www.aem.gob.mx/). As a consequence, the Universidad
Autónoma de Nuevo León, in the city of Monterrey, organized a
series of National Planetary Astrophysics Workshops. The first
was in 2013 and the second in 2015 (http://tasp.fcfm.uanl.mx/).
155
Astronomers from all over México were invited to present their
research and encouraged to cooperate and plan projects related to
the study of Solar System objects or extrasolar planets.
One of the results from the latest meeting was the organization of
the
2015
Mexican
Asteroid
Photometry
Campaign
(http://www.astro.uson.mx/~lorenzo/CMFA2015/CMFA2015). The
objective of this first campaign was to organize, coordinate, and
share photometric observations of asteroids between interested
parties at various national observatories and university research
centers. Because asteroid photometry is not a common activity
amongst Mexican astronomers, it was decided as a first effort to
form individual observing groups that would start to develop their
own expertise in the matter by observing relatively simple targets.
Three asteroids were chosen: the C-class main-belt asteroid 1084
Tamariwa has a well-defined period, large amplitude, and is
relatively bright. 1466 Mundleria, another C-class inner-belt
asteroid, is a smaller and dimmer target with an unknown rotation
period. 4055 Magellan was also selected since the V-type Amor
asteroid would have a favorable opposition during 2015.
We present the results of this first Mexican Asteroid Photometry
Campaign. In all we collected 18 nights of observations from three
different observatories and managed to reconstruct full lightcurves
for 1084 Tamariwa and 4055 Magellan. 1466 Mundleria turned out
to be a more difficult target to observe and analyze since it was
dim, in a crowded field of stars, and apparently exhibits a very
small brightness amplitude variation.
At the Universidad de Monterrey (UdeM) Observatory (MPC 720)
we observed all three asteroids on 10 different nights using a
Meade 0.36-m f/8 LX-600GPS telescope and an SBIG STL-1301E
CCD. The camera contains a 1280×1024-16µm KAF-1301E/LE
chip which covers a ~26.3×21.1 arcminute field-of-view (FOV)
with an image scale of about 1.25 arseconds/pixel. All asteroids
were observed unfiltered and exposures were set for each target as
follows: 40 seconds for fast-moving 4055 Magellan, 60 seconds
for 1084 Tamariwa, and 120 seconds for dim 1466 Mundleria. The
CCD images were read in 2×2 binned format for faster download
time and improved observing efficiency. The FOV was maintained
fixed in the chip by using a guide star at all times.
Two observing runs were scheduled with the 0.84-m f/15 RitcheyChretien telescope at the Observatorio Nacional de San Pedro
Mártir (SPM; MPC 679) in Baja California for this program. This
telescope uses a 2048×2048×13.5 µm Spectral Instruments CCD
for regular imaging. This combination yields a FOV of ~6.3×6.3
arcminutes with an approximate image scale of 0.185
arcsecond/pixel. 1084 Tamariwa was observed for only one night
on the first observing run in May, while 4055 Magellan was
observed for three nights and 1466 Mundleria for two nights on the
second observing run in August. All images were obtained using
an off-axis guide star for stability (although the field drifted a bit
during the observing sessions) and were also unfiltered and binned
2×2 for efficiency. Exposure times varied for each target: 30 and
45 seconds for 4055 Magellan, 90 and 120 seconds for 1466
Mundleria, and 60 seconds for 1084 Tamariwa.
One observing night for 1084 Tamariwa and two for 1466
Mundleria were recorded at the Carl Sagan Observatory belonging
to the Universidad de Sonora in Hermosillo. The observatory
operates a Meade LX-200 0.41-m f/10 telescope equipped with a
2499×2499×12 µm Apogee Alta F9000 CCD for imaging. This
yields a 25.4×25.4 arcminute FOV with an image scale of ~0.61
arcsecond/pixel. The images at this site were obtained unguided,
unfiltered and – in this case – unbinned. Exposure times were 20
seconds for 1084 Tamariwa and 50 seconds for 1466 Mundleria.
All the data were concentrated at the Universidad de Monterrey
Observatory where the photometric analysis was performed using
MPO Canopus (version 9.5.0.14). Images were also processed in
the standard manner using nightly dark current and flat-field files
from each site.
1084 Tamariwa. This asteroid was observed at the Carl Sagan
Observatory (2015 April 22), Universidad de Monterrey
Observatory (2015 April 28-30), and San Pedro Mártir Observatoy
(2015 May 13). During analysis, the April 22 observations from
Carl Sagan Observatory were treated as two separate sessions due
to re-centering the FOV during the night.
The asteroid was previously observed and reported by Behrend et
al. (2007), Stecher et al. (2008), and Sada (2008). Our
observations confirm the period of 6.195 ± 0.001 h, amplitude
~0.30 magnitudes, and general lightcurve shape presented in Sada
(2008).
The similarity of both lightcurves obtained at different opposition
dates (2007 August 19 and 2015 April 21) would suggest a
rotational axis alignment perpendicular to the ecliptic, although too
few complete lightcurves are available for a full polar orientation
and shape analysis. We note in particular that the main minimum
(without the “hump”) exhibits a large scatter in both the 2007 and
2015 lightcurves. We are uncertain as to its origin but it might be
associated with topographical features sensitive to slight variations
in phase angle illumination.
As an aside, initial analysis of the April 28 observations at the
Universidad de Monterrey Observatory found the intended
comparison star, GSC 5553-0670 (magnitude ~13.4), to be
variable. It was discarded for the asteroid measurements but
follow-up analysis found a sinusoidal lightcurve of short period.
We plan to obtain more data and report the results to the AAVSO.
This serves both as a warning to make sure comparison stars are
not variable and a reminder that asteroid images can be data mined
for other objects.
1466 Mundleria. This asteroid was observed for four nights at the
Universidad de Monterrey Observatory (2015 July 25 and 27 and
August 6-7), two nights at the San Pedro Mártir Observatory (2015
August 20-21), and two nights at the Carl Sagan Observatory
(2015 June 15-16). Despite being the most observed asteroid in the
156
set, no conclusive brightness variations larger than 0.03
magnitudes could be detected over a single observing session.
Therefore, no rotational period could be derived. This small (~22
km.) asteroid was the faintest in our set and, at the time, was also
crossing a dense star field in Ophiuchus. These circumstances
combined to make the data reduction difficult, even with the star
eliminating option in MPO Canopus, and yielded relatively large
scatter for the smaller UdeM and Carl Sagan Observatory
telescopes. The SPM data were of much better quality but sparser.
Nevertheless, it was useful to set our magnitude variation upper
limit. No other reports for this asteroid were found. A larger
aperture instrument and more patience are required to derive a
lightcurve for this asteroid.
4055 Magellan. This NEA was observed for three nights at the
Universidad de Monterrey Observatory (2015 August 14, 18-19)
and three more nights at the San Pedro Mártir Observatory (2015
August 19, 22-23). The derived lightcurve exhibits similar maxima
and minima with a period of 7.479 ± 0.001 hours and a relatively
large amplitude of ~0.45 magnitudes. The August 19 data were
acquired independently at both the UdeM and SPM observatories.
The August 22 SPM data were analyzed as two separate sessions
because of recentering of the FOV due to the asteroid’s fast sky
motion.
Our August 18 UdeM data show large scatter due to weather but
assure full lightcurve phase coverage. The August 14 UdeM data
exhibited even larger scatter and were omitted from the period and
lightcurve shape calculations even though its general outline does
corroborate our derived final lightcurve.
This asteroid has been observed several times. Warner (2014)
suggests a period of ~6.384 hours from sparse 2004 data over a
7.475-hour period initially proposed by Pravec et al. (2000).
However, older observations reported in Waszczak et al. (2015)
and observations from the current 2015 opposition by Warner
(2015) and Behrend et al. (2015) favor the later ~7.5-hour period.
Our results are consistent with this period estimate, amplitude and
general lightcurve shape.
Acknowledgments
The results presented in this report were partially based on
observations acquired at the Observatorio Astronómico Nacional
in the Sierra San Pedro Mártir (OAN-SPM), Baja California,
México. We also would like to thank Ricardo López-Valdivia for
his aid during the OAN-SPM August observations.
References
Behrend, R. (2007, 2015). “Asteroids and Comets Rotation
Curves, CdR.” http://obswww.unige.ch/~behrend/page_cou.html
Pravec, P., Wolf, M. Sarounova, L. (2000). “Ondrejov Asteroid
Photometry Project.”
Sada, P.V. (2008). “Lightcurve Analysis of 1084 Tamariwa.”
Minor Planet Bulletin 35, 50.
Stecher, G., Ford, L., Lorenzen, K., Ulrich, S. (2008).
“Photometric Measurements of 1084 Tamariwa at Hobbs
Observatory.” Minor Planet Bulletin 35, 76-77.
Bulletin 41, 157-168.
CS3-Palmer Divide Station: 2015 March-June.” Minor Planet
Bulletin 42, 256-266.
Waszczak, A., Chang, C.-K., Ofek, E.O., Laher, R., Masci,
F., Levitan, D., Surace, J., Cheng, Y.-C., Ip, W.-H., Kinoshita,
D., Helou, G., Prince, T.A., Kulkarni, S. (2015). “Asteroid
Lightcurves from the Palomar Transient Factory Survey: Rotation
150, id. 75.
PHOTOMETRY OF ASTEROIDS
2014 EK24 AND 2015 FS332
AT THE TERSKOL OBSERVATORY
Vira Godunova, Volodymyr Reshetnyk, Maxim Andreev
ICAMER Observatory of NASU (MPC B18)
27 Acad Zabolotnoho Str.
Kyiv 03680 UKRAINE
[email protected]
Andrii Simon, Volodymyr Vasylenko
Taras Shevchenko National University of Kyiv
Kyiv, UKRAINE
(Received: 2016 January 15 Revised: 2016 March 11)
Future Mexican Asteroid Photometry Campaigns are being
planned with an increasing number of proposed targets (main-belt
asteroids and NEAs) and participation from other Mexican
observatories. We are also working on standardizing the observing
sequences and data reduction and analysis techniques to make the
data easier to share and publish.
We report photometric observations of two near-Earth
asteroids that were obtained with the Zeiss-600 telescope
at the Terskol Observatory in 2015. Based on our data,
we were able to estimate the rotation properties of these
asteroids.
Starting in 2003, the facilities of the Terskol Observatory in the
Northern Caucasus (43°16'29" N, 42°30'03" E, 3120 m ASL) have
157
been heavily used for follow-up studies of solar system small
bodies (Tarady et al., 2010). The 60-cm Cassegrain telescope
(Zeiss-600) is the main instrument for follow-up astrometry,
photometry, and spectroscopy of asteroids. This f/12.9 reflector has
two CCD cameras. The most recently installed camera is an SBIG
STL-1001 based on 1024x1024 CCD with 24 micron pixels that
provides a field of view of 10.9' x 10.9'. The limiting V magnitude
for this telescope is 21.0m. In 2003-2015, positions of more than
250 NEAs were measured to an accuracy of about 0.2-0.3 arcsec.
Those astrometric data have been continuously reported to the IAU
Minor Planet Center.
in the shape of the lightcurve based on our data from that reported
by Warner (2016), when the phase angle was about 65°. However,
a period of P = 2.406 ± 0.001 h and an amplitude of A = 0.65,
which were obtained by Warner, are consistent with our estimates
obtained at a phase angle of 92°.
Special software was developed to process spectral and
photometric datasets. To determine the rotation properties of
observed asteroids, methods based on Fourier analysis, Lomb
normalized periodogram, and phase dispersion minimization
(PDM) were used. In 2015, complete lightcurves were obtained for
a number of NEAs. Here we provide the recent results for asteroids
2014 EK24 and 2015 FS332.
2014 EK24. This Apollo-type asteroid (D ~ 70 m) is on NASA’s
list of potential human mission targets; therefore, studies of its
physical properties are currently required. 2014 EK24 was
observed at Terskol on 2015 February 23, when it made a close
approach (16 lunar distances) to the Earth. Photometric
observations were performed over one night (UT 00:10:12 to
02:58:44). In order to enhance the signal-to-noise ratio, all CCD
images were taken in “white light” (a clear filter), with the
exposure time of 20 s.
Data processing was performed using MaxIm DL and our own
software. Images were calibrated with bias, flat, and dark frames.
Observations of a photometric standard star (SA105-437) were
used to reduce data to V band.
To find the period of the lightcurve, the PDM technique
(Stellingwerf, 1978) was applied. Furthermore, we checked the
result using the n normalized periodogram method (Lomb, 1976)
and found that these two techniques produced a similar result: a
rotational period of P = 0.0998 ± 0.0001 h. The lightcurve has an
amplitude of A = 0.83 ± 0.15 mag.
Acknowledgements
This work has been supported by the NASU-KNU project
No.
0114U003875. V. Godunova acknowledges a grant from the
European Astronomical Society awarded to her in 2015.
References
Lomb, N.R. (1976). “Least-squares frequency analysis of
unequally spaced data.” Ap&SS 39, 447-462.
Stellingwerf, R.F. (1978). “Period determination using phase
dispersion minimization.” Ap. J. 224, 953-960.
Tarady, V., Sergeev, O., Karpov, N., Zhilyaev, B., Godunova, V.
(2010). “Observations with Small and Medium-Sized Telescopes
at the Terskol Observatory.”
http://arxiv.org/ftp/arxiv/papers/1003/1003.4875.pdf
2015 FS332. Photometric observations of this potentially
hazardous asteroid (D ~ 600-1400 m) were obtained at the Terskol
Observatory over one night on 2015 September 20 (begin UT
16:44 on September 20; end UT 01:52 on September 21), or before
its close approach to the Earth within 18.6 lunar distances on 2015
October 4. Analysis of the data found a period of
P = 2.401 ± 0.003 h and an amplitude of A = 0.84 ± 0.12. The raw
observations and phased lightcurve for 2015 FS332 are shown,
respectively, in the plots below. We note the significant differences
Warner, B.D. (2016). “Near-Earth Asteroids Lightcurve Analysis
at CS3-Palmer Divide Station: 2015 June-September.” Minor
158
ASTEROIDS OBSERVED FROM CS3:
2015 OCTOBER - DECEMBER
Robert D. Stephens
Center for Solar System Studies (CS3)/MoreData!
11355 Mount Johnson Ct., Rancho Cucamonga, CA 91737 USA
[email protected]
Lightcurves for 5 asteroids were obtained from the
Center for Solar System Studies from 2015 October to
December.
CCE photometric observations of four main-belt and one Nearearth asteroids observed at Center for Solar System Studies (CS3,
MPC U81). During this quarter, this observatory was observing
Jovan Trojans asteroids. When a bright moon swamped the Trojan
cloud with moonlight, other targets were selected because of their
known short rotational periods and because they were well away
from the Moon. These observations were acquired so that over
time pole positions and shape models can be calculated.
All images were made with a 0.4-m or a 0.35-m SCT using an FLI
Proline 1001E or FLI Microline 1001E CCD camera. Images were
unbinned with no filter and had master flats and darks applied to
the science frames prior to measurement. Measurements were
made using MPO Canopus, which employs differential aperture
photometry to produce the raw data. Period analysis was done
using MPO Canopus, which incorporates the Fourier analysis
algorithm (FALC) developed by Harris (Harris et al., 1989).
Catalog magnitudes were taken from the MPOSC3 catalog, which
is based on the 2MASS catalog (http://www.ipac.caltech
.edu/2mass) but with magnitudes coverted from J-K to BVRI using
formulae developed by Warner (2007). The nightly zero points
using this catalog have been found to be consisted to about ± 0.05
magnitude, but are occasionally higher.
The Reduced Magnitude in the Y-axis of plots below is Johnson V.
These values have been converted from sky magnitudes to unity
distance by applying –5*log (rΔ) to the measured sky magnitudes
with r and Δ being, respectively, the Sun-asteroid and Earthasteroid distances in AU. The magnitudes were normalized to the
given phase angle, e.g., alpha(6.5°), using G = 0.15, unless
otherwise stated. The X-axis is the rotational phase ranging from –
0.05 to 1.05.
5806 Archieroy. This Hungaria has been determined several times
in the past by Warner (2005, 2008, 2013), all resulting in a
rotational period of 12.16 h. Observations were obtained this year
are in hope of leading towards pole solution model. This year’s
result of 12.187 h is in good agreement with the prior results.
(20932) 2258 T-1. Parvec reported a rotational period of 4.3239 h
for this inner main-belt asteroid. Behrend (2015) reported possible
Number
5806
20932
48470
52748
163000
Name
Archieroy
2258 T-1
1991 TC2
1998 JJ1
2001 SW169
2015
mm\dd
11/26-11/30
11/28-12/15
10/01-10/10
10/24-11/02
10/11-10/31
Pts
Phase
253
9
118
5
366
312
550
17.2,16.6
10.1,17.6
9.4,7.4
7.9,6.0,6.1
2.5,21.8
attenuation events, but the scatter of about 0.1 mag. in the
observations was too great to resolve any eclipses. Behrend
reported a rotational period of 4.3237 h. Based upon the Behrend
report, we started observations concurrent with their run, reducing
the scatter to 0.01 mag. Over the observing run from 28 November
to 17 December, three attenuations events of about 0.05 mag. on
30 November, 03 December, and 05 December were detected.
However, a satisfactory fit to an orbital solution for a satellite
could not be done. This asteroid should be considered a prime
candidate to reobserve at its next opposition in March 2017.
(48470) 1991 TC2. The rotational period for this Hungaria has
been determined twice before (Warner 2011, 2014) with reported
periods of 10.48h and 10.19 h. The result found this year of 10.504
h is in good agreement with the 2011 result.
(52748) 1998 JJ1. No previously reported results could be found in
the Lightcurve Database (LCDB; Warner et al., 2009).
(163000) 2001 SW169. This Amor asteroid was observed on nine
nights in 2008 by the Lowell Observatory Near-Earth Asteroid
Photometric Survey (Skiff 2012). The observations resulted in a
partial, asymmetric lightcurve showing a rotational period of 38.04
h which they reported as not convincing. No night covered more
than 10 percent of the rotational phase, there was little overlap, and
the scatter was large. This year’s campaign, resulting in a 70 h
rotational period, covers substantially more of the lightcurve with
sufficient overlap.
References
Parvec, P. (2015). Photometric Survey for Asynchronous Binary
Asteroids web site.
http://www.asu.cas.cz/~asteroid/binastphotsurvey.htm
Skiff, B.A., Bowell, E., Koehn,B.W., Sanborn, J.J.; McLelland,
K.P., Warner, B.D. (2012) “Lowell Observatory Near-Earth
Asteroid Photometric Survey (NEAPS) - 2008 May through 2008
December.” Minor Planet Bul. 39, 111-130.
Warner, B.D.,(2005). “Asteroid lightcurve analysis at the Palmer
Divide Observatory - fall 2004.” Minor Planet Bul. 32, 29-32.
Warner, B.D. (2007). “Initial Results from a Dedicated H-G
Project.” Minor Planet Bul. 37, 57-64.
Divide Observatory: December 2007 - March 2008.” Minor
Planet Bul. 35, 95-98.
Divide Observatory: 2010 December- 2011 March.” Minor Planet
Bul. 38, 142-149.
LPAB
BPAB
69
51
13
36
18
25
6
-10
8
3
Period
12.187
4.3245
10.504
4.258
69.97
P.E.
0.003
0.0001
0.006
0.001
0.05
Amp
0.46
0.09
0.09
0.73
0.45
A.E.
0.02
0.01
0.02
0.02
0.05
Grp
H
MB-I
H
H
NEA
159
Divide Observatory: 2012 September - 2013 January.” Minor
Warner, B.D. (2014). “Asteroid Lightcurve Analysis at CS3Palmer Divide Station: 2014 March-June.” Minor Planet Bul. 41,
235-241.
Acknowledgements
This research was supported by NASA grant NNX13AP56G. The
purchase of the FLI-1001E CCD camera was made possible by a
2013 Gene Shoemaker NEO Grant from the Planetary Society.
160
ASTEROIDS LIGHTCURVES ANALYSIS:
2015 OCTOBER–DECEMBER
pixel. At G.V. Schiaparelli Astronomical Observatory the images
were obtained with a 0.60-m f/4.64 reflector and CCD SBIG ST10XME (2184×1672 pixels, 6.8 microns) with a field-of-view of
18.4×12.3 arcmin and a scale of 1.51 arcsec per pixel.
Albino Carbognani
Astronomical Observatory of the
Aosta Valley Autonomous Region (OAVdA)
Lignan 39, 11020 Nus (Aosta) ITALY
[email protected]
We used MPO Canopus (Warner, 2015) version 10.7.0.6 for
differential photometry and period analysis. When possible, the
sessions were calibrated with the MPO Canopus Comp Star
Selector (CSS), which chooses comparison stars that are similar in
color to the target (in general, solar-type stars), and the
“DerivedMags” approach.
Luca Buzzi
G.V.Schiaparelli Astronomical Observatory
Varese ITALY
Eight asteroids, main-belt (MBA) and near-Earth (NEA),
were observed in 2015 Oct–Dec: 6853 Silvanomassaglia,
(112985) 2002 RS28, (155110) 2005 TB, (163899) 2003
SD220, (253106) 2002 UR3, (337866) 2001 WL15,
2015 XC, and 2015 WG9.
6853 Silvanomassaglia is an MBA. A total of 88 images were
taken with a clear filter on only one night for a total of 4.5 hours of
observation. The bimodal lightcurve appears completely covered.
The rotation period is 2.796 ± 0.025 h with an amplitude of 0.12
mag. Considering that this asteroid is relatively large
(H = 14.5, or D = 2–8 km) and that the period is close to the spinbarrier value of 2.2 h, it appears to be a good candidate to be a
binary system. No rotation period had been reported before our
observations.
This paper features the results of photometric observations of
main-belt (MBA) and near-Earth (NEA) asteroids made in the
period 2015 Oct–Dec at OAVdA (Carbognani et al., 2007) in
collaboration with G.V. Schiaparelli Astronomical Observatory. In
general we tried to observe asteroids whose rotation periods were
not known (or at least uncertain) at the time of observations. It was
not possible to determine the rotation period for all the observed
asteroids, but the data collected are nevertheless provided for all
the objects (Table I).
Number
Name
Dates
Phase
yyyy mm dd deg
6853
2015 11 08
Silvanomassaglia
Period
h
Amp
mag
5.9
2.796
±0.025
0.12
(112985)
2002 RS28
2015 11 16
44.6
3.44
±0.07
0.06
(155110)
2005 TB
2015 10 23
2015 11 05
2015 11 06
25.1
19.2
3.482
±0.001
0.43
(163899)
2003 SD220
2015 11 06
2015 11 07
81.8
long
>0.2
(253106)
2002 UR3
2015 11 16
2015 11 17
2015 11 19
7.0
13.4
2.478
±0.002
0.05
2015 12 01
2015 12 08
45.9
63.3
2.435
±0.03
0.12
(337866)
2001 WL15
2015 11 27
2015 12 01
24.6
24.1
5.1
±0.1
0.13
2015 XC
2015 12 02
11.5
0.2767
±0.0001
0.39
2015 WG9
2015 11 28
36.0
?
>0.4
Table I. The number/name or provisional designation, date of
observations, range of phase angles, rotation period and amplitude
for the observed asteroids.
The images at OAVdA were captured by means of a modified
Ritchey-Chrétien 0.81-m f/7.9 telescope equipped with an FLI
1001E CCD with an array of 1024×1024 pixels. This gave a fieldof-view of 13.1×13.1 arcmin and a plate scale was 1.54 arcsec per
(112985) 2002 RS28 is an Amor asteroid with its rotation period
known at the time of the observations but still uncertain (Warner,
2016a). This target was observed on a single night session about 5
hours long, which produced a total of 100 images taken with a
clear filter and exposure times of 180 s. With our data, the most
probable period is about 3.4 hours, but the lightcurve amplitude is
very low so the uncertainty persists.
161
(163899) 2003 SD220 is an Aten object that made its Earth flyby
on 2015 Dec 24 at 0.073 AU. A total of 222 images using a clear
filter were taken over nine hours in two nights. The raw lightcurves
are almost constant and without features. No rotation period was
determined. Warner (2016b) found a period of 285 h and
amplitude of 2.2 mag and the possibility that the asteroid might be
in a low-level tumbling state.
(155110) 2005 TB is an Apollo object which made its Earth flyby
on 2015 Oct 18 at 0.366 AU. A total of 346 images were taken
with a clear filter on three nights: 2015 Oct 23, Nov 5 and 6. The
data from Nov 5 were discarded because of too many clouds. The
result is a period value of 3.482 ± 0.001 h with an amplitude of
about 0.43 mag. The period, unknown at the time of our
observations, is in good agreement with that reported by Warner
(2016b).
(253106) 2002 UR3 is an Apollo object which made its Earth flyby
on 2015 Nov 28 at 0.33 AU. This asteroid was observed during six
nights but the data from only three were suitable for photometry
due to cloudy skies. The data from the November sessions show a
very low amplitude lightcurve (0.05 mag) with the most probable
period being around 2.5 hours.
162
asteroid was too close to brighter stars were deleted, which broke
the continuity of the lightcurve. The most probable period is
around 5 h. No period was known for this object before.
Because of the uncertainty of the first result, we repeated the
observations in early December. We were able to confirm the
period of about 2.5 hours, aided by the fact that due to the
increased phase angle, the lightcurve amplitude also increased
from 0.05 to about 0.12 mag.
2015 XC is an Apollo asteroid which made its Earth flyby on 2015
Dec 8 at 0.086 AU. The case of this asteroid is similar to that of
2015 WG9. Immediately after the astrometric observations were
sent to the MPC, a photometric observing run of 1.2 hours was
made. Later, a 22-minute run was made by Buzzi and the data were
included in the analysis.
Warner (2016b) gives a period of 180 h and amplitude of 0.36 mag
with the possibility that the asteroid might be tumbling. It’s not
clear why the two results are so different.
(337866) 2001 WL15 is an Amor object which made its Earth
flyby on 2016 Jan 16 at 0.080 AU. In the first session, differential
photometry of this object was made impossible by a full Moon
only 17 degrees from the target. In the second session (6 hours
long), the asteroid was in a crowded star field. Images where the
163
References
Carbognani, A., Calcidese, P. (2007). “Lightcurve and Rotational
Period of Asteroids 1456 Saldanha, 2294 Andronikov and 2006
NM.” Minor Planet Bulletin, 34, 18-19.
Warner, B.D., Harris, A.W, Pravec, P. (2009). “The asteroid
Lightcurve Database.” Icarus, 202, 134-146. Updated 2105 Dec 7.
Warner, B.D. (2015). MPO Software, MPO Canopus. Bdw
Publishing. http://minorplanetobserver.com/
Warner, B.D. (2016a). “Near-Earth Asteroid Lightcurve Analysis
at CS3-Palmer Divide Station: 2015 June – September.” Minor
Overall, a total of 141 images with no filter and exposure times of
60 and 15 s were taken. Photometry was made difficult by the low
signal-to-noise ratio of the asteroid (mag +18.4, SNR about 10-15)
and by its high angular velocity (8 arcsec/minutes). The lightcurve
is noisy but the amplitude is high (0.39 mag). The resulting period
is about 17 minutes. Considering this fact and that the diameter of
the asteroid is in the range 20-60 m, it can be considered to be an
elongated, strength-bound body. No period was known for this
object before.
2015 WG9 is an Apollo object classified as a potentially hazardous
asteroid (PHA). It made an Earth flyby on 2015 Nov 21 at 0.065
AU. A total of 95 images with clear filter and exposure time of 60
s were taken in a session of about 1.5 hours immediately after
astrometric measurements of the asteroid were sent to the Minor
Planet Center (MPC). The asteroid had a V magnitude of about
+17.7 and sky motion of 8 arcsec/minute, which made it a difficult
target. The lightcurve is very noisy and does not show any obvious
periodicity. The Fourier analysis shows weak periodicity due to
temporal sampling only. No period was known for this object
before.
Warner, B.D. (2016b). “Near-Earth Asteroid Lightcurve Analysis
at CS3-Palmer Divide Station: 2015 October-December.” Minor
(53110) 1999 AR7: A NEW NEA BINARY DISCOVERY
Brian D. Warner
(CS3-PDS)
446 Sycamore Ave.
Eaton, CO 80615 USA
[email protected]
Analysis of CCD photometric observations of the nearEarth asteroid (53110) 1999 AR7 made in 2015
December show it to be a binary system with a primary
period of 2.7375 ± 0.0005 h and orbital period of 31.31 ±
0.02 h. The depth of the secondary mutual event
indicates a minimum effective diameter ratio (Ds/Dp) of
0.41 ± 0.02.
The near-Earth asteroid (NEA) (53110) 1999 AR7 was observed as
part of the ongoing program at Center for Solar System Studies
(CS3) to determine the rotation periods and other photometric
characteristics of NEAs and to support radar observations with
optical lightcurves. The initial observations were made at the
Palmer Divide Station at CS3 (CS3-PDS) starting on 2015 Dec 19.
See Tables I and II for equipment observing circumstances.
OBS
Telescope
Camera
CS3-PDS 0.35-m f/9.6 Schmidt-Cass
STL-1001E
Table I. Telescope/cameras used at each location.
Location
CS3-PDS
Acknowledgements
This research made use of the NASA’s Astrophysics Data System
and JPL’s Small-Body Database Browser. Research at the
Astronomical Observatory of the Aosta Valley Autonomous
Region was supported by a 2013 Shoemaker NEO Grant. Work at
the G. V.Schiaparelli Astronomical Observatory was supported by
a 2015 Shoemaker NEO Grant.
2015
Phase
LPAB
BPAB
Dec 19-31
21.3-27.2
101-100
14-25
Table II. Observing circumstances. Phase is the phase angle, in
degrees. LPAB and BPAB are, respectively, the phase angle
bisector longitude and latitude, also in degrees. For rows with a
range of dates, the values are for the first and last date in the range.
All values are computed for 0 h UT.
The observations from Dec 19-21 seemed to indicate an object
having a lightcurve with a period of about 33 hours and a shape
with pronounced, sharp minimums and possibly even “shoulders”
164
which are significant increases in the slope on the descending part
of a minimum and decrease on the ascending part. Such a
lightcurve is often considered evidence of a near- or full-contact
binary asteroid. The latter would be two lobes of about equal size
joined by a narrow bridge.
However, with later observing runs, the long period trend seemed
to disappear was replaced by a distinct short period (2-3 hours)
lightcurve. Figure 1 shows the unsubtracted lightcurve after
combining all sessions. The short period component is very
apparent but there are a number of data points well below the
average curve. Following the Dec. 27 observing run, a dual-period
search was employed using MPO Canopus.
The process involved searching for a period between 2-5 hours
without subtracting any data points. This led to an initial solution
of about 2.7 hours. The resulting Fourier model curve was
subtracted from the data during the search for a second period,
which found a strong solution at about 31 hours. That result was
subtracted from the original data set and the search for the short
period started anew. This process continued until both periods
stabilized.
Figure 3. The lightcurve for 1999 AR7 after subtracting the one due
to the primary clearly shows the mutual events (occultations and/or
eclipses) due to the satellite.
The lightcurve in Figure 3 outside the events is essentially flat,
indicating that the satellite is nearly spheroidal as well. Otherwise,
the periods outside the events might show an upward “bowing.”
The dips in the flat sections, most notably at 0.9 rotation phase, are
artifacts due to the high harmonic order fit required for the model
lightcurve to follow the events all the way to the bottom.
The final result explains why analysis of the first few sessions was
led awry: they were capturing the events almost exclusively, which
gave a misleading impression of what was happening and of the
true nature of the asteroid. When the observation window moved
away from the events and so included only the rotation of the
primary, the fact of the asteroid being a “simple” binary became
more apparent.
Figure 1. The complete data set for 1999 AR7 forced to a period
between 2.5-3.0 hours but without subtracting a secondary period.
Because of the deep minimums in the long period lightcurve, an
8th-order fit was used while only a 4th-order fit was used for the
short period. Figures 2 and 3 show the final results. The primary
(Figure 2) has a period of 2.7375 ± 0.0005 h and amplitude of 0.10
mag. The latter indicates a nearly spheroidal body. Figure 3 shows
the mutual events, i.e., occultations and/or eclipses due to the
satellite, and gives an orbital period of 31.31 ± 0.02 h.
The depths of the two events range from about 0.17-0.20 mag. The
shallower event allows estimating the effective diameter ratio of
the two bodies using
Ds D p ≥
10 0.4Δm − 1
(1)
where m is the magnitude drop of the shallower event. This gives
€
Ds/Dp ≥ 0.41 ± 0.02
where the actual error may be larger.
Note that this is a minimum value because neither event is “flatbottomed,” which would indicate a total eclipse. Therefore, only
partial eclipses were seen and so the value gives a minimum size
ratio. Note also that the events are asymmetrical in the sense that
they are not 0.5 rotation phase apart. This may indicate an
eccentric orbit for the satellite. Additional data at future apparitions
will help model the system.
Acknowledgements
provided by NASA grant NNX13AP56G.
Figure 2. The lightcurve for the primary of 1999 AR7 indicates a
nearly spheroidal body.
165
5425 VOJTECH: A NEW BINARY VESTOID
Robert D. Stephens
Center for Solar System Studies (CS3) / MoreData!
11355 Mount Johnson Ct.
Rancho Cucamonga, CA 91737 USA
Brian D. Warner
Eaton, CO USA
CCD photometry observations made in 2015 October
and November of the Vestoid asteroid 5425 Vojtech
showed it to be binary. The primary lightcurve has a
period of 2.64759 ± 0.000004 h and an amplitude 0.27 ±
0.02 mag. The orbital period of the satellite is 25.43 ±
0.02 h. Based on mutual events ranging from 0.05 to
0.09 mag, the estimated effective diameter ratio of the
two bodies is Ds/Dp ≥ 0.22 ± 0.02.
without a filter. Table I gives the observation circumstances over a
span of almost three weeks.
The raw images were flat-field and dark subtracted before being
measured in MPO Canopus. Night-to-night linkage was aided by
the Comp Star Selector utility which helps find near-solar color
comparison stars, thus reducing color difference issues. Stars were
chosen from the MPOSC catalog, which is based on the 2MASS
catalog (http://irsa.ipac.caltech.edu/Missions/2mass.html). The
J-K magnitudes in 2MASS were converted to V magnitudes using
formulae by Warner (2007). Generally, the zero points are within
±0.05 of one another, but larger adjustments can be required to
minimize the RMS value from the Fourier analysis.
Period analysis was also done in MPO Canopus, which employs
the FALC Fourier analysis algorithm developed by Harris (Harris
et al., 1989). The initial observations at the end of October did not
show any signs of a satellite. However, starting with the Nov 2
observing run, there were apparent deviations from the single
period lightcurve (“No Sub” plot) that required further
investigation using the dual-period function.
Based on its orbital parameters, the asteroid 5425 Vojtech is
believed to be a member of the Vestoid orbital group (Warner et
al., 2009). True Vestoids, those that were part of the original
parent body of Vesta, would have an albedo on the order of
pv ~ 0.4 However, the orbital space includes a large number of
interlopers. This may be the case for Vojtech since its albedo of pv
= 0.243 ± 0.074 (Masiero et al., 2012) is more like that of a type S
asteroid (Warner et al., 2009).
Vojtech was observed as part of an on-going asteroid lightcurve
program at the Center for Solar System Studies (CS3) that
concentrates mostly on near-Earth and Hungaria asteroids as well
as Jupiter Trojans. When none of those are available, other targets
are chosen to avoid idle telescope time.
The only previous lightcurve result in the asteroid lightcurve
database (LCDB; Warner et al., 2009) was from Vander Haagen
(2012), who reported a bimodal lightcurve with a period of
2.648 h and amplitude of 0.27 mag. That lightcurve showed no
obvious signs of a satellite even though the phase angle bisector
longitude (see Harris et al., 1984) was only 25° from the one
during the 2015 observations. Why this might happen is discussed
later.
2015 mmm/dd
Oct
Oct
Nov
Nov
Nov
Nov
Nov
Nov
Nov
Nov
Nov
26
27
02
05
06
07
08
09
10
11
19
Phase
13.2
12.7
9.9
8.6
8.1
7.6
7.2
6.8
6.4
6.0
4.5
LPAB
54.4
54.5
54.9
55.1
55.2
55.2
55.3
55.3
55.4
55.4
55.7
BPAB
6.8
6.9
7.1
7.2
7.3
7.3
7.3
7.4
7.4
7.4
7.6
In the dual-period search process, an initial value is found for the
dominant (usually shorter) period. The Fourier model lightcurve is
subtracted from the data set in the succeeding search for a second
period. The Fourier curve for that second period is subtracted from
the data set in a new search for the dominant period. If, for
example, the dominant solution produces a trimodal instead of
bimodal lightcurve (the latter being the presumptive choice), the
initial search is started anew but the period search range is
restricted to eliminate finding the trimodal solution. The iterative
process continues until both periods stabilize and it produces
reasonable lightcurves.
Table I. Observing circumstances for 5425 Vojtech. The last two
columns are the phase angle bisector longitude and latitude (see
Harris et al., 1984). The values were computed for 8 h UT, or about
the middle of each observing run.
The observations were made by Stephens using a 0.35-m SchmidtCassegrain telescope with Finger Lakes MicroLine PL-1001E
CCD camera. The 300-second exposures were unguided and made
166
The dual period analysis found a primary lightcurve of
P1 = 2.64759 ± 0.00004 h, A1 = 0.27 ± 0.02 mag (“P1” plot).
Assuming an equatorial view of the asteroid, this leads to an a/b
ratio of the asteroid’s silhouette of 1.28:1. Subtracting this
lightcurve from the data set and doing a period search found a
solution that clearly shows mutual events (occultations and/or
eclipses) due to a satellite (“P2” plot). The lightcurve has a period
of PORB = 25.43 ± 0.02 h, AORB = 0.05-0.09 mag.
Outside the events, the lightcurve was essentially flat, which likely
indicates a nearly spheroidal shape for the satellite that is probably
tidally-locked to the orbital period.
References
444 Gyptis.” Icarus 57, 251-258.
3, 24, 60, 261, and 863.” Icarus 77, 171-186.
Nugent, C., Cabrera, M.S. (2012). “Preliminary Analysis of
Vander Haagen, G.A. (2012). “Lightcurves of 724 Hapag, 2423
Ibarruri, 4274 Karamanov, 4339 Alamater, and 5425 Vojtech.”
LIGHTCURVE ANALYSIS
OF THE HUNGARIA BINARY 7958 LEAKEY
Using the shallower event of 0.05 mag and
where m is the depth of the shallower event in magnitudes, gives
Ds/Dp ≥ 0.22 ± 0.02. Since neither event was total, the estimate is
a minimum value and could be larger.
Each observing run covered about eight hours, or about 1/3 the
orbital period and short enough for the observing window to be
placed between the two events and so show no indications of the
satellite. Each day, the window moved about 0.06 period phase to
the left. Eventually, as happened starting Nov 2, the window
started to cover one of the events. The slow migration, however,
meant observing the asteroid for a prolonged period to get
sufficient coverage of the secondary lightcurve.
Robert D. Stephens
Center for Solar System Studies (CS3) / MoreData!
11355 Mount Johnson Ct.
Rancho Cucamonga, CA 91737 USA
Brian D. Warner
Eaton, CO USA
Alessandro Marchini
Astronomical Observatory, DSFTA - University of Siena (K54)
Via Roma 56, 53100 - Siena, ITALY
Fabio Salvaggio
21047 – Saronno, ITALY
Riccardo Papini
Carpione Observatory (K49)
San Casciano in Val di Pesa (FI), ITALY
It’s likely that Vander Haagen encountered this problem during his
observations in 2012 and so, by a stroke of poor luck, observed on
four nights when the observing window did not include one of the
events.
Acknowledgements
Science Foundation grant AST-1507535.
The Hungaria asteroid 7958 Leakey is a known binary
(Warner et al., 2012). It was observed in 2015 to confirm
and refine the original periods for the primary rotation
and satellite orbit. The analysis of the 2015 data found a
noticeably different orbital period. We report on the
analysis of the new data and a second look at the data
from 2012.
The Hungaria asteroid 7958 Leakey was found to be a binary by
Warner et al. (2012). They reported a primary lightcurve
parameters of P = 2.34843 h, A = 0.22 mag and orbital period of
167
50.29 h. Observations were made by three of the authors in 2015 to
check on those earlier results and, if possible, refine the orbital
period of the satellite.
For the sake of convenience and easier comparison, the
observational details and plots from the 2012 results are repeated
here. Table I lists the equipment used by each observer. Tables II
and III give the observing circumstances for the two apparitions.
There were no obvious signs of mutual events at either apparition,
but both times the secondary lightcurve showed a low-amplitude
bimodal lightcurve that is usually attributed to a the rotation of an
elongated satellite that is tidally-locked to the orbital period.
The 2012 Apparition
The raw images were flat-field and dark subtracted before being
measured in MPO Canopus. Night-to-night linkage was aided by
the Comp Star Selector utility which helps find near-solar color
comparison stars, thus reducing color difference issues. Stars were
chosen from the MPOSC catalog, which is based on the 2MASS
catalog (http://irsa.ipac.caltech.edu/Missions/2mass.html). The
J-K magnitudes in 2MASS were converted to V and R magnitudes
using formulae by Warner (2007). Generally, the zero points are
within ±0.05 of one another, but larger adjustments can be required
to minimize the RMS value from the Fourier analysis.
All exposures at both apparitions were unfiltered. Stephens and
Warner used V magnitudes from the MPOSC in the Comp Star
Selector while Marchini and Salvaggio used R magnitudes. This
required an additional zero point offset of the data from the latter
two observers by approximately the V-R color index of the
asteroid before the period analysis could begin. This was also done
in MPO Canopus, which employs the FALC Fourier analysis
algorithm developed by Harris (Harris et al., 1989).
Obs
Telescope
Camera
Warner
Stephens
Marchini
Salvaggio
0.35-m
0.35-m
0.30-m
0.24-m
SBIG STL-1001E
FLI ML-1001E
SBIG STL-6303E
SBIG ST8-XME
f/9.1 SCT
f/11 SCT
f/5.6 Mak-Cass
f/10 SCT
Only a recap of the 2012 observations is given here. See Warner et
al. (2012) for more details. The “No Sub” plot shows the result of
a period search without subtracting a model lightcurve. The search
range was limited to 1-6 hours based on the appearance of the
individual lightcurves. There are obvious attenuations from the
average lightcurve, which is what prompted the search for a
satellite in 2012.
Obs
Warner
2012 Jun
13
17-20
23-27
Sess
α
LPAB
BPAB
All
21.7
21.9-22.1
22.4-22.9
266
266
267
31
32
32
LPAB
BPAB
29
29
29
30
30
30
30
30
30
30
-4
-5
-8
-8
-10
-11
-8
-11
-11
-8
Table II. Observation circumstances, 2012.
Obs
Stephens
Marchini
Salvaggio
2015 Oct
4
7-14
19
21-23
24
29-31
23
30
31
23
Sess
α
1-2
14.7
3-18
12.8-8.9
19
7.1
20-25
6.8-6.9
28-29
7.1
30-33,35,36 8.9-9.9
26
6.9
34
9.4
37
9.9
27
6.9
Table III. Observation circumstances, 2015. a is the solar phase
angle. The last two columns are, respectively, the phase angle
bisector longitude and latitude (see Harris et al., 1984).
The dual period search for the period of the primary and orbit of
the satellite were conducted by first finding an approximate period
for the primary without subtracting any data points that might be
due to the mutual events (occultations/eclipses) or rotation of the
satellite. This gave a model lightcurve for the satellite. This was
subtracted from the data set in a new search for the primary period.
The iterative processed continued until both periods stabilized.
The two “Natural” plots show the final result of a new dual period
search where the periods were allowed to float and find the best
168
possible fit for each one, as judged by minimizing the RMS error
in the Fourier analysis. The new analysis found different periods
from the original analysis done in 2012.
The data set spanned only two weeks. For the secondary period,
there are gaps in coverage as well as minimum overlap in other
sections. This leads to the fact that the actual error in the secondary
period is probably several times the formal error of ±0.09 h.
The 2015 Apparition
Stephens began observations in early October as part of the
Hungarias follow-up program at the Center for Solar System
Studies. In this case, the point was to confirm the existence of a
satellite, preferably by capturing mutual events, which provide
more definitive proof than just a secondary lightcurve. Given the
very long period for the satellite orbit and that it was nearly
commensurate with an Earth day, additional observations from
Marchini and Salvaggio were requested. Both observers were in
locations significantly different in longitude from CS3, which
allowed them to observe parts of the secondary period that were
not being covered at CS3.
The “No Sub” plot again shows the entire data set used in a single
period search near the expected period for the primary body. The
signs of the satellite are not quite as visible given the much larger
number of data points and, as will be seen, a slightly lower
amplitude of the secondary lightcurve.
The two “Natural” plots show the results of the dual period search
where both periods were allowed to float and so find the best
possible RMS fit for both. In other words, the results from 2012
were used to guide but not force any given solution.
Note that the primary periods from 2012 and 2015 are very similar.
They would not necessarily be expected to be identical since these
are synodic periods and so subject to variation from one apparition
to the next due to different viewing aspects. On the other hand, the
secondary periods have are noticeably different but this is more
likely due to overstated uncertainties and the difference in
coverage.
While the 2015 secondary lightcurve does have a small gap, it is
based on a data set with considerably more data points that were
obtained over a longer period and, more important, includes data
from diverse longitudes, which reduces ambiguities when working
with a period nearly commensurate with an Earth day. The higherquality of the 2015 data set is further demonstrated by comparing
the period spectra for P2 from both apparitions, where the
spectrum from 2015 show a more clearly, but not sharply, defined
minimum.
169
A Common Solution
The orbital period of the satellite does not change from one
apparition to the next. There may be very slight differences due to
different viewing aspects, especially if the orbit is not perfectly
circular. However, those cannot account for the difference of
almost 2.5 hours between the two apparitions. Since the 2015 data
set provided a more certain solution, we decided to use it as a
foundation for finding a common period for the orbit and so found
solutions for P1 based on forcing P2 = 49.5 ± 0.5 h. This covers the
period found in 2015 and almost so for 2012 if using an
uncertainty of 1.0 hour for that result.
First, compare the P2 lightcurves forced to 49.5 h. The one from
2012 has even more significant gaps but a second-order Fourier fit
is still reasonable. There are no gaps in the 2015 lightcurve but the
fit is not quite as good and required some additional zero point
offsets to bring some sessions closer to the model curve. Based on
these two plots, we adopt a value of P2 = 49.5 ± 0.5 for the orbital
period of the satellite.
Next compare the two P1 (primary) lightcurves, both period and
apparent quality of fit, against the “Natural” solutions. The forced
fit in 2012 is noticeably poorer while there is little difference in the
2015 lightcurve. Also worth noting is that the “Natural” and
“Forced” periods within each apparition were essentially identical.
As noted above, it would not be expected that the periods would be
the same from one apparition to the next.
Conclusion
The two important lessons from this exercise are the value of
follow-up observations and, even more, the value of collaborations
involving observers from well-separated longitude when dealing
with a long period, especially if the period is an integral or halfintegral multiple of 24 hours.
Given the very long orbital period, mutual events will be difficult
to observe with sufficient precision. There were hints of those in
the 2012 apparition, which were used to estimate an effective
diameter ratio of satellite-to-primary of 0.30. Additional
observations of high quality involving a number of observers are
strong encourage at future apparitions.
Acknowledgements
Funding for Stephens and Warner was provided by NASA grant
NNX13AP56G.
References
444 Gyptis.” Icarus 57, 251-258.
3, 24, 60, 261, and 863.” Icarus 77, 171-186.
Warner, B.D., Coley, D., Harris, A.W. (2012). “Lightcurve for
7958 Leakey: a New Hungaria Binary.” Minor Planet Bull. 39,
240-241.
170
PHOTOMETRIC OBSERVATIONS OF
3958 KOMENDANTOV:
A PRELIMINARY APPROACH TO DEEPER STUDIES
Cristian F. Chavez
Department of Mechanical Engineering
Pontificia Universidad Católica de Chile
[email protected]
This is just a first approach to future deeper studies because several
nights of images are needed to get a better idea of the actual
period. However, from the limited data set, it is probably safe to
say that the asteroid is not a fast rotator (P < 3 h) and it might be
possible to obtain a reliable period within a reasonable span of
time.
(Received: 2016 January 15 Revised: 2016 February 1)
Asteroid 3958 Komendantov was observed remotely
through the most powerful instrument available in the
Virtual Telescope Project 2.0 during two sessions
performed in 2015 September. Analysis of the data tends
to conclude that the asteroid is not a fast rotator.
Main-belt asteroid 3958 Komendantov was discovered on
1953 October 10 by Pelagueya Fiodórovna Shain at Simeiz
Observatory, Crimea. It was named in honor of Russian
astronomer Nikolaj Vasil'evich Komendantov (1895-1937), a staff
member of the Astronomical Institute in Leningrad, and a
recognized enthusiast in minor planet research (JPL, 2016).
Despite being a numbered asteroid that was discovered several
decades ago, there is almost no literature about it. No rotation
period could be found in the LCDB (Warner et al., 2009) or in the
Minor Planet Center (MPC, 2016) or NASA Jet Propulsion
Laboratory (JPL, 2016) databases. The only information that could
be found was about the orbital parameters and absolute magnitude
(JPL, 2016) and its spectral type, Xc (Bus and Binzel, 2002a,
2002b). The lack of information about the physical parameters of
the asteroid prompted the decision to choose it from the list of
lightcurve photometry opportunities for 2015 July-September
(Warner et al., 2015).
The images were taken using the Virtual Telescope Project 2.0 in
Ceccano, Italy, because of the quality in services and low cost
(VTP 2016). The telescope was a Planewave 0.43-m f/6.8
corrected Dall-Kirkham (CDK) astrograph on a Paramount ME
robotic mount. The CCD camera was an SBIG STL-6303E
working at –15°C.
Since no period was known for Komendantov, the strategy was to
take one-minute exposures every two minutes (a cycle of 1 + 2 = 3
minutes) for a couple of hours to get an idea of its period for future
sessions and, hopefully, to obtain enough images to cover either a
maximum or minimum in the lightcurve and so determine an
approximate period. A total of two sessions were performed on the
night of 2015 September 12. Unfortunately, bad weather and the
observatory schedule did not allow obtaining more data.
After downloading the 80 FITS images, they were measured with
MPO Canopus version 10.4.3.17 (Warner, 2013) through a
differential photometry technique. The program was also used to
perform a Fourier analysis using the FALC algorithm developed
by Harris (Harris et al., 1989) in order to find the rotation period
for the asteroid.
The preliminary estimate for the synodic period is about 6 hours;
however, given the amplitude of at least 0.2 magnitude and the fact
that the curve does not show a clear minimum, the final result is
more likely a bimodal lightcurve with a period of 12 hours or
more, i.e., approximately double the period given with the
monomodal lightcurve shown here.
Acknowledgments
I would like to thank Brian Warner for his invaluable support in
the use of MPO Canopus software while I was doing my research.
References
Bus, S., Binzel, R.P. (2002a). “Phase II of the Small Main-Belt
Asteroid Spectroscopic Survey: The Observations.” Icarus 158,
106-145.
Bus, S., Binzel, R.P. (2002b). “Phase II of the Small Main-Belt
Asteroid Spectroscopic Survey: A Feature-based Taxonomy.”
Icarus 158, 146-147.
24, 60, 261, and 863.” Icarus 77, 171-186.
JPL (2016). NASA Jet Propulsion Laboratory Solar System
Dynamics web site. http://ssd.jpl.nasa.gov/
MPC (2016) Minor Planet Center web site.
http://www.minorplanetcenter.net
VTP (2016). Virtual Telescope Project 2.0.
http://www.virtualtelescope.eu
lightcurve database.” Icarus 202, 134-146. Updated 2015 Dec 7.
Warner, B.D. (2013). MPO Canopus software, version 10.4.3.17.
BDW Publishing, Eaton, CO.
Warner, B.D., Harris, A.W., Pravec, C., Durech, J., Benner,
L.A.M. (2015). “Lightcurve Photometry Opportunities: 2015 JulySeptember.” Minor Planet Bull. 42, 228-232.
171
LIGHTCURVES OF ASTEROIDS
891 GUNHILD AND 1614 GOLDSCHMIDT
Janus Kozdon, Sarah Cantu, Kent Montgomery
Texas A&M University-Commerce
P.O. Box 3011
Commerce, TX 75429-3011 USA
Lightcurves were determined for asteroids 891 Gunhild
and 1614 Goldschmidt. A rotational period of 10.556 ±
0.003 hours was found for 891 Gunhild and 8.873 ±
0.003 hours for 1614 Goldschmidt.
asteroid. These values are then averaged for that image. The
lightcurves were constructed using the differential magnitude
plotted versus time. Fourier transforms were then used to
determine the rotation rates of the asteroids.
The lightcurves were used to create models of the asteroids using
MPO LCInvert v.2.4.0.0 (Bdw Publishing, 2012). To create the
asteroid model, the software calculates and creates many standard
triangles which are fitted together to produce the shape of the
asteroid. The shape of the asteroid as it rotates produces a
lightcurve which is then matched to the data in order to check for
consistency. However, the data from this study were taken without
a large variety of solar phase angles. Therefore, the shape of the
asteroid is only an estimate.
Results
This study determined the rotational period of two asteroids. The
declination, apparent magnitude, and opposition date were the
criteria used to choose which asteroids were imaged. A declination
between 5° and –30° is optimum for both telescopes used in this
study. An apparent magnitude of 16 or brighter is preferred.
Asteroids near opposition were chosen because they allowed
imaging all night. Asteroids 891 Gunhild and 1614 Goldschmidt
were the two asteroids that satisfied the criteria.
Asteroid 891 Gunhild was discovered by Wolf in 1918 May and its
orbital period is 4.83 Earth years (JPL). With a semi-major axis of
2.86 AU, it resides in the main asteroid belt. Its orbital eccentricity
is 0.03 while its orbital inclination is at 13.56 degrees. The
estimated diameter is 52 kilometers.
Schmitt discovered 1614 Goldschmidt in 1952. It has an orbital
period of 3.86 years and is a main-belt asteroid with a semi-major
axis of 2.99 AU and an estimated diameter of 46 kilometers (JPL).
Its eccentricity is 0.07 and the orbital inclination is 14.07 degrees.
Method
Two different telescopes from the Southeastern Association for
Research on Astronomy (SARA) consortium were used for
observing the asteroids. They were the SARA-North facility at Kitt
Peak National Observatory in Arizona and the SARA-South
facility at Cerro Tololo Inter-American Observatory near La
Serena, Chile. The SARA-North telescope has a diameter of 0.9-m
and SARA-South has a diameter of 0.6-m. Both telescopes are of
Cassegrain design and were equipped with Apogee CCD cameras
and filter wheels. The CCD cameras were cooled using liquid
nitrogen in order to reduce electronic noise.
Images taken each night were reduced and aligned using Maxim
DL. Reductions were performed with flat, bias, and dark images
taken on the same night. New flat, bias, and dark images were
taken each night. All flat-field images were taken against the
twilight sky. The dark frames were imaged using three minute
exposures, which was equivalent to the light frame exposures of
the asteroid. Filters used were IR-Blocking at SARA-North and
Luminance5 at SARA-South. Both filters are clear in the visible
part of the spectrum but block the IR portion of the spectrum.
After image reduction and calibration, the magnitude of the
asteroid was determined using MPO Canopus v10.4.0.8 (Warner,
2011). Differential aperture photometry was used for the
measurements. Aperture photometry measures the light which falls
inside a given region and subtracts off the brightness of the sky in
a larger annulus surrounding the star. Differential photometry takes
the difference in magnitude between five comparison stars and the
891 Gunhild. Images were taken using both SARA telescopes with
exposure times of 180 seconds. At SARA-North, 147 images were
taken 2015 July 2. At SARA-South, 85 images were taken on 2015
July 7. A period of 7.93 ± 0.01 hours with amplitude variation of
0.18 magnitudes was previously determined (Stephens, 2000). The
period determined in this study was 10.556 ± 0.003 hours with
amplitude variation of 0.18 magnitudes. Another study determined
the rotational period to be 11.853 hours (Behrend, 2005). The
period determined in this study had the advantage that, during one
of the observing nights, there was more than one complete
rotational period of data. This allowed us to rule out the previously
published periods, even though there are several gaps in the
lightcurve.
1614 Goldschmidt was imaged 105 times at SARA-North on 2015
June 14 and 53 times on June 24. At SARA-South, 151 images
were taken 2015 July 4. A previous study found a rotational period
of 7.74 ± 0.02 hours with amplitude variation of 0.1 magnitudes
(Warell, 2015). This study found a period of 8.873 ± 0.003 hours
with a similar amplitude of 0.10 mag. The study of Warell suffered
from large errors in the brightness of the asteroid that made it
difficult to determine an accurate rotation rate. However, the
lightcurve found in this study does not have complete coverage and
so the rotational period may still have some uncertainty. It is also
difficult to explain the observations which fall below the fit curve
at phase 0.50.
References
Bdw Publishing (2012).
http://www.minorplanetobserver.com/MPOSoftware/
MPOLCInvert.htm
JPL Small-Body Database Browser.
Stephens, R.D. (2000). “Rotational Periods and Lightcurves of 891
Gunhild and 1017 Jacqueline.” Minor Planet Bull. 27, 54-55.
Warell, J. (2015). “Lightcurve Observations
Goldschmidt.” Minor Planet Bull. 42, 21-22.
of
1614
Warner, B.D. (2011). MPO Canopus version 10.4.0.8. Bdw
Publishing. http//www.MinorPlanetObserver.com
172
Figure 1. Lightcurve of 891 Gunhild with a period of 10.556 hours
Figure 4. Preliminary shape model for 1614 Goldschmidt.
LIGHTCURVE AND
ROTATION PERIOD DETERMINATION FOR
2616 LESYA AND (28910) 2000 NH11
Fabio Salvaggio
21047 – Saronno, ITALY
[email protected]
Lorenzo Franco
Alessandro Marchini
via Roma, 56, 53100 – Siena, ITALY
Riccardo Papini
San Casciano in Val di Pesa (FI), ITALY
Figure 2. Preliminary shape model for 891 Gunhild.
Photometric observations of the main-belt asteroids 2616
Lesya and (28910) 2000 NH11 were made in 2015
December. For 2616 Lesya, analysis found a bimodal
lightcurve with a period of 9.219 ± 0.001 h. For (28910)
2000 NHA, the result was a bimodal lightcurve with a
period of 5.970 ± 0.002 h.
2616 Lesya was discovered on 1970 August 28 by Tamara
Smirnova. It’s a typical main-belt asteroid in an orbit with a semimajor axis of about 2.16 AU, eccentricity 0.08, and orbital period
of about 3.18 years. The estimated diameter is about 60 km
(Masiero et al., 2012).
Figure 3. Lighcurve of 1614 Goldschmidt with a period of 8.873
hours
Observations were made on five nights from 2015 December 1120 with a total of 238 useful data points collected over the interval
173
of 9 days. During this time, the phase angle ranged from 2.7° to
7.6° after opposition.
At the Astronomical Observatory of the University of Siena, data
were obtained with a 0.30-m f/5.6 Maksutov-Cassegrain telescope,
SBIG STL-6303E CCD camera, and clear filter; the pixel scale
was 2.26 arcsec in binning 2x2. Exposures were 300 seconds. At
the Balzaretto Observatory, data were obtained with a 0.20-m
Schmidt-Cassegrain (SCT) reduced to f/5.5 equipped with a SBIG
ST7-XME CCD camera; the pixel scale was 1.65 arcsec and the
exposure times were of 420 sec.
The period analysis yielded several possible solutions that stand
out in the period spectrum with nearly comparable RMS errors.
We concluded that the most likely solution was a bimodal
lightcurve with a period 5.971 ± 0.002 hours and amplitude of 0.65
± 0.06 mag, confirming the value obtained from Waszczak et al.
(2015).
References
The period analysis yielded several possible solutions that stand
out in the period spectrum with nearly comparable RMS errors.
We concluded that the most likely solution was a bimodal
lightcurve with a period of 9.219 ± 0.001 hours and amplitude of
0.43 ± 0.03 mag.
(28910) 2000 NH11 was discovered on 2000 July 10 by Paulo R.
Holvorcem. It’s a typical main-belt asteroid in an orbit with a
semi-major axis of about 2.75 AU, eccentricity 0.08, and orbital
period of about 4.56 years. According to Mainzer et al. (2011), the
estimated diameter is about 5 km.
Observations were made on five nights from 2015 December 1017 with a total of 188 useful data points collected over the interval
of 7 days, during which the phase angle ranged from 5.6° to 8.1°
after opposition. Data were obtained at the Astronomical
Observatory of the University of Siena with the same equipment
used for 2616 Lesya, with exposure times of 300 seconds.
Mainzer, A., Grav, T., Bauer, J., Masiero, J., McMillan, R.S.,
Cutri, R.M., Walker, R., Wright, E., Eisenhardt, P., Tholen, D.J.,
Spahr, T., Jedicke, R., Denneau, L., DeBaun, E., Elsbury, D.,
Gautier, T., Gomillion, S., Hand, E., Mo, W., Watikins, J.,
Wilkins, A., Bryngelson, G.L., Del Pino Molia, A., Desai, S.,
Gomez Camus, M., Hidalgo, S.L., Konstantopoulos, I., Larsen,
J.A., Maleszewski, C., Malkan, M.A., Mauduit, J.-C., Mullan,
B.L., Olszewski, E.W., Pforr, J., Saro, A., Scotti, J.V., Wasserman,
L.H. (2011). “NEOWISE observations of near-Earth objects:
Preliminary results.” Ap. J. 743, A156.
Nugent, C., Cabrera. (2012). “Preliminary Analysis of
150, A75.
174
TWENTY-THREE ASTEROIDS LIGHTCURVES AT
OBSERVADORES DE ASTEROIDES (OBAS):
2015 OCTOBER - DECEMBER
Amadeo Aznar Macías
Isaac Aznar Observatory, Valencia, SPAIN
POP-Punto Observación de Puzol, Valencia, SPAIN
[email protected]
Alfonso Carreño Garcerán
Zonalunar Observatory,Valencia, SPAIN
Enrique Arce Mansego
Vallbona Observatory, Valencia, SPAIN
Pedro Brines Rodriguez
TRZ Observatory, Valencia, SPAIN
Juan Lozano de Haro
Elche Observatory, Alicante, SPAIN
Alvaro Fornas Silva, Gonzalo Fornas Silva
Oropesa Observatory, Castellón, SPAIN
Vicente Mas Martinez
CAAT, Centro Astronómico del Alto Turia, SPAIN
Onofre Rodrigo Chiner
Bétera Observatory, Valencia, SPAIN
Table I shows the equipment at the observatories that participated
in this work. We concentrated on asteroids with no reported period
and those where the reported period needed confirmation. All the
targets were selected from the Collaborative Asteroid Lightcurve
(CALL) web site at http://www.MinorPlanet.info/call.html, paying
special attention to keeping the asteroid’s magnitude within reach
of the telescopes being used. We tried to observe asteroids at a
phase angle of less than 15°, but this was not always possible.
The image scale at each observatory was optimized to the average
seeing at the given location. All images were binned 1x1 and were
guided. Exposure times ranged from 60 to 200 seconds. MPO
Canopus was used to measure the images by employing
differential aperture photometry. The images were calibrated with
bias, dark, and flat frames before measurement. Star subtraction
was used where necessary and possible to minimize the effects on
the asteroid measurements (Aznar, 2013).
Table II lists the individual results along with the range of dates for
the observations and the number of nights that observations were
made.
618 Elfriede. This MBA has an estimated diameter of 120
kilometers. Behrend (2004) found a period of 14.75 h and
amplitude of 0.17 mag. Warner (2006) reported P = 14.801 h,
A = 0.12 mag. Carbo et al. (2008) found a period of 14.85 h and
We observed Elfriede on four nights during the period of 2015
Nov 11 to Dec 20. We found a synodic rotation period of 14.795 ±
0.001 h and lightcurve amplitude of 0.14 mag. These are consistent
with the previous results.
We report on the photometric analysis results for 23
main-belt asteroids (MBA) done by Observadores de
Asteroides (OBAS). This work is part of the Minor
Planet Photometric Database that was initiated by a
group of Spanish amateur astronomers. We have
managed to obtain a number of accurate, complete
lightcurves as well as some additional incomplete
lightcurves to help analysis at future oppositions.
In this issue we publish the results for 23 asteroids analyzed under
the
Minor
Planet
Photometric
Database
project
(http://www.minorplanet.es). This project is focused on collecting
lightcurves for main-belt asteroids using photometric techniques.
This database shows graphic results of the data, mainly
lightcurves, with the data phased to a given period. We invite all
astronomers to consult this database.
Observatory
Zonalunar
Telescope (meters) CCD
0.10 refractor
Atik 383L+
OIA,Obs Isaac Aznar
0.35 SCT
SBIG STL1001E+AO
POP-Puzol
0.25 SCT
SBIG ST9-XE+AO
Vallbona
0.25 SCT
SBIG ST7-XME
TRZ
0.20 R-C
QHY8
Elche
0.25 DK
SBIG ST8-XME
Oropesa
0.20 SCT
Atik 16I
Bétera
0.23 SCT
Atik 314L+
CAAT
0.43 DK
SBIG STX-11K
662 Newtonia is a main-belt with H = 10.3. The IRAS database
(Tedesco et al., 2004) indicates a diameter of 23.6 km and albedo
of 0.1999 based on H = 10.5. Behrend (2006) found a period of
16.46 h based on incomplete coverage of the lightcurve. Other
results include Chang et al. (2014; 20.6 h) and Waszczak et al.
(2015; 21.4285 h).
Our analysis found a period of 21.095 ± 0.001 h and amplitude of
0.42 mag, which is in good agreement with the Waszczak et al.
period, especially given that it based on a limited number of data
points. Because the phase angle was more than 25°, the shape and
amplitude of the lightcurve may have been affected by shadowing
effects.
Table I. List of instruments used for the observations. SCT is
Schmidt-Cassegrain. R-C is Ritchey-Chrétien. DK is Dall-Kirkham.
175
Date Range
2015 mm/dd
Nights
Period (h)
Error (h)
Amp
Phase
618 Elfriede
11/11 – 12/30
4
14.795
0.001
0.14
-13.9,+3.1
662 Newtonia
10/22 – 11/14
11
21.10
0.001
0.42
-30.6,-25.0
764 Gedania
09/15 – 11/20
3
19.16
0.04
0.13
+4.9,+18.4
838 Seraphina
11/08 – 11/16
5
17.62
0.001
0.13
-4.2,-0.8
1001 Gaussia
11/17 – 11/28
5
20.99
0.01
0.11
+2.3,+5.5
1013 Tombecka
11/23 – 11/29
4
6.05
0.001
0.44
+5.7,+8.0
1018 Arnolda
1242 Zambesia
11/18 – 11/20
09/25 – 10/29
4
6
14.57
15.72
0.01
0.14
0.39
0.15
+5.6,+6.3
-14.5,+6.2
1343 Nicole
11/16 – 11/18
3
14.76
0.01
0.38
-1.1,+0.8
1480 Aunus
12/17 – 12/29
2
3.10
0.01
0.32
-16.5,-15.4
1531 Hartmut
12/19 – 12/24
8
25.4
0.01
0.26
+15.5,+17.3
2104 Toronto
11/18 – 11/19
3
8.97
0.01
0.26
-2.4,-2.2
2118 Flagstaff
2343 Siding Spring
10/16 – 10/29
11/03 – 11/16
5
3
15.17
2.11
0.01
0.01
0.35
0.15
+8.1,+14.4
+3.4,+11.7
2947 Kippenhahn
11/19 – 11/28
2
10.43
0.001
0.43
-2.2,+5.4
3433 Fehrenbach
11/30
1
3.922
0.001
0.28
+4.8
3606 Pohjola
11/28 – 12/04
4
2.92
0.01
0.11
-2.0,+1.3
3811 Karma
09/25 – 10/29
4
13.23
0.01
0.33
-9.5,+10.5
4212 Sansyu-Asuke
10/22 – 11/08
6
15.94
0.01
0.09
-5.1,+4.8
4272 Entsuji
6350 Schluter
10/15 – 11/03
10/29 - 11/08
8
3
2.81
13.19
0.01
0.001
0.07
0.31
-3.9,+11.9
+7.2,+10.4
10064 Hirosetamotsu
11/29 – 12/01
4
8.06
0.01
0.74
+12.0,+13.2
10907 Savalle
11/12 – 11/14
2
608
0.001
0.07
+1.3,+2.3
Number Name
Table II. Dates of observation, number of nights, and derived periods/amplitudes. The Phase column gives the phase angle. If
there are two values, they represent, respectively, the phase angle on the first and last dates in the range at 0h UT. Pre-opposition
phase angles are negative; post-opposition phase angles are positive.
764 Gedania is a C-type main-belt asteroid with H = 9.6. The
estimated diameter is 58.3 km and albedo is 0.0840 (Tedesco et al.,
2004). There were two rotation periods reported prior to our
observations. The first one was 24.817 h (Brinsfield, 2010), based
on observations in 2009, and the other was 24.9751 h (Behrend,
2006).
The OBAS group obtained a rotation period of 19.13 ± 0.01 h and
amplitude of 0.1 mag. Looking at the period spectrum, we
conclude that this is not a secure solution. Observations at future
oppositions will be required to find a more secure period.
176
838 Seraphina. Seraphina is a main-belt asteroid that has been
studied several times in the past. Tedesco et al. (2004) found a
dimeter of 59.8 km and albedo of 0.0455. It has been classified as a
taxonomic type P asteroid. Reported periods include 15.67 h from
Behrend (2005) and 16.2 h from Binzel (1987). Both results are
based on less than full coverage.
Using our data and the resulting period spectrum, we conclude that
the rotation period could be 17.62 ± 0.01 hours. The amplitude of
the lightcurve is 0.13 magnitudes. This amplitude does not match
with the other amplitudes found by Behrend (0.07 mag) or Binzel
(0.30 mag), but this could be due to different view aspects (polar
vs. equatorial views) at the different oppositions.
1013 Tombecka. This is a medium-sized main-belt asteroid (31.93
km) with an albedo of 0.1552 (Tedesco et al., 2004).
We selected this asteroid in order to check the quality of results
found by a new OBAS member since the period is well-known.
The analysis done by the new member found a rotation period of
6.050 ± 0.001 hours and amplitude of 0.44 mag. These closely
match previous results from Behrend (2006; 6.0508 h) and
Fauerbach et al. (2008; 6.053 h)
1001 Gaussia. The IRAS database (Tedesco et al., 2004) gives a
dimeter of 74.6 km and albedo of 0.0392 for this main-belt
asteroid. As of 2015 December, only two rotation periods had been
reported. The first one (Behrend, 2005) is 4.08 hours with an
amplitude of 0.04 mag. This result was given U = 1 (likely wrong)
in the asteroid lightcurve database (LCDB; Warner et al., 2009).
The second rotation period was obtained by Bonzo and Carbognani
(2009). They found P = 9.17 h and A = 0.16 mag. This result is
rated U = 2– in the LCDB. These results are based on less than full
coverage, which is the reason why we selected this object to
improve the rotation period solution.
The rotation period calculated by OBAS in this campaign is 20.99
± 0.01 h. The lightcurve shows a bimodal shape with a maximum
lightcurve amplitude of 0.11 magnitudes.
1018 Arnolda. This is a medium-sized main-belt asteroid (16.42
km) with an albedo is 0.3701 (Tedesco et al., 2004). Binzel (1987)
found a period of 11.97 h. More than 20 years later, two other
results were published: 10.00 h (Behrend, 2011) and 14.617 h
(Pligge et al., 2011). The lightcurve obtained by OBAS has a
period of 14.57 ± 0.01 hours, similar to that of Pligge et al.
The lightcurve shows a bimodal shape with a maximum amplitude
of 0.39 magnitudes, which also nearly matches Pligge et al. This is
not surprising because the phase angle bisector longitude (Harris et
al., 1984) in 2015 was almost 180° away from the longitude in
2010 when Pligge et al. observed the asteroid. This means that the
viewing aspects were along the same line but looking at different
hemispheres of the asteroid. Observations at a longitude about 90°
from those in 2015, or about 140°, might result in a lightcurve with
a much different shape or amplitude. This would give an idea of
the direction that the spin axis of the asteroid points.
177
1480 Aunus. This main-belt asteroid was discovered in 1938 by
Vaisala. There were no entries in the LCDB. Analysis of our data
obtained on two nights in 2015 December found a bimodal
lightcurve with a period of 6.10 ± 0.01 hours and amplitude of 0.32
mag.
1242 Zambesia. Tesdesco et al. (2004) give this main-belt a
diameter of 47.7 km and geometric albedo as 0.0708. Pozzoli
(2003) reported a period of 17.305 h and amplitude of 0.24 mag.
However, the lightcurve was not published and so this result
cannot be considered certain.
The OBAS team analyzed this asteroid during its 2015 opposition
and the result is not definitive. The lightcurve shows a rotation
period of 15.72 ± 0.14 hours and an amplitude of 0.15 magnitudes.
Cloudy weather prevented additional observations beyond the six
nights we did observe.
1343 Nicole. Nicole is a main-belt asteroid of about 24 km
diameter and H = 11.0. Warner (2009) found a period of 14.77
hours based on less than full coverage and said that the period
could be wrong. The OBAS team observed Nicole on three nights
in 2015 November. Our analysis found a period of 14.76 ± 0.01 h,
which is very similar to the one reported by Warner. The
lightcurve has an amplitude of 0.38 mag.
1531 Hartmut. The only other period for this main-belt asteroid
was reported by Klinglesmith et al. (2016), who reported a period
of 25.57 h and amplitude of 0.21 mag based on observations in
2015 November. Our data, obtained on eight nights in 2015
December led to a rotation period of 25.63 ± 0.01 hours and a
maximum lightcurve amplitude of 0.26 magnitudes. The period is
very similar to the one found by Klinglesmith et al. (2016).
2104 Toronto. This MBA was found to have a rotation period of
8.9669 h by Oey (2006) at Blue Mountain Observatory. His
lightcurve was almost complete, missing only a small portion.
However it was rated U = 2+ because of large gaps between
observing sessions and the small missing section. This rating
indicates that the period is very likely correct, but not absolutely
so. It is “almost secure.”
The asteroid was included in this project in order to get a more
certain determination of the period. Based on a complete bimodal
lightcurve, we found a period of 8.97 ± 0.01 h with an amplitude of
0.26 mag. The period is almost identical to the period found by
Oey (2006).
178
period of 20.01 h, which they attribute to a possible third member
of the system.
2118 Flagstaff. This MBA was analyzed in 2007 by Vander
Haagen (2008). He reported a rotation period of 15.1557 hours
with only a small gap in the lightcurve. The LCDB gives a U = 2+
rating, which means that the solution is very likely correct. Vander
Haagen kindly provided his data to Aznar for additional analysis.
After reprocessing all the Vander Haagen sessions, we concluded
that the rotation period in 2007 was 15.19 ± 0.01 hours and the
lightcurve amplitude obtained was 0.25 magnitudes.
The OBAS team selected this object in order confirm the earlier
results. Our complete lightcurve shows a rotation period of 15.17
hours, consistent with the result determined by Vander Haagen in
2008.
Both lightcurves show a similar period but they have maximum
amplitudes that differ by about 0.1 magnitudes. This difference can
be explained in part by the difference in phase angles at the time of
the observations. The Vander Haagen observations were at about
13° while the OBAS observations were at about 23°. Another
reason could be that the phase angle bisector longitudes differed by
about 20 degrees between the two oppositions (Brian D. Warner,
private communications) and so the viewing aspects were not the
exactly the same.
2343 Siding Spring. This is a binary main-belt asteroid. The
satellite was detected in 2015 by Pollock et al. (2015). The
effective diameter of the system is about 5 km and the primary’s
rotation period is 2.10637 h. The satellite has an orbital period of
11.789 h and an effective diameter of about 0.19 that of the
primary (Pollock et al., 2015). The group also reported a secondary
Plot “1” shows the lightcurve using the data from the three
observatories that followed the asteroid: TRZ, Betera, and Isaac
Aznar. Although two observatories of OBAS team detected the
effect of the secondary asteroid in the lightcurve (Betera and Isaac
Aznar) we used only the Isaac Aznar Observatory data for
computing the rotation period and lightcurve amplitude of the
primary. The analysis found P = 2.10 ± 0.01 h and A = 0.17 mag.
179
Plot “2” shows the lightcurve without removing the effects of the
satellite. Plot “3” shows the primary asteroid lightcurve after
removing the effects of the satellite.
2947 Kippenhahn. This is an MBA discovered in 1955. It was
previously analyzed by Chiorny et al. (2011). Their analysis was
based on absolute photometry of small main-belt asteroids from
which they found a rotation period of 10.5 hours and amplitude of
0.42 magnitudes. They also found a color index of V–R = 0.507.
Because these results were based on incomplete coverage of the
lightcurve, we chose this asteroid in order to get the full lightcurve
and find a secure period.
Based on two nights of observations, we found that the rotation
period is 10.430 ± 0.001 hours and the lightcurve amplitude is 0.35
mag.
3606 Pohjola. There were no previous entries in the LCDB
(Warner et al., 2009) for this main-belt asteroid. Our solution
indicates a slightly asymmetric bimodal lightcurve with a period of
2.92 ± 0.01 h and a maximum amplitude of 0.11 magnitudes.
3433 Fehrenbach. This is a binary MBA discovered in 1963. The
satellite was discovered by Pray et al. (2015), who found the
primary rotation period to be 3.9160 h; the satellite is tidallylocked to its orbital period of 19.665 h, i.e., its rotation period is
also its orbital period.
We observed the asteroid on one night and found the main
lightcurve period of 3.922 hours with an amplitude of 0.28 mag.
Plot “1” shows the data from Isaac Aznar Observatory with the
effects of the satellite removed while Plot “2” shows the data set
without subtracting the effects of the satellite.
3811 Karma. The only previously reported period for Karma is
from Behrend (2007), who found a period of 11.52 h and
amplitude of >0.20 mag. This result is based on less than full
coverage. We were able to obtain a complete lightcurve in 2015.
Our analysis found a period of 13.23 ± 0.01 h and amplitude of
0.33 mag.
180
4212 Sansyu-Asuke. This MBA was discovered in 1987. It appears
that this is the first reported lightcurve for Sansyu-Asuke. We
followed the asteroid for eight nights. Cloudy weather did not
allow collecting more observations, so our result must be
considered preliminary.
Our lightcurve does not show a bimodal shape, maybe because it
has a long period asteroid or the viewing aspect was nearly poleon. Our analysis found a rotation period of 15.94 ± 0.01 h and
10064 Hirosetamotsu is a main-belt asteroid discovered in 1988.
Hanus et al. (2015) reported a sidereal period based on lightcurve
inversion of 12.128 hours. Behrend (2015) and Casalnuovo (2016)
found almost identical periods of 8.05 hours. Our lightcurve shows
a bimodal shape with a period of 8.06 ± 0.01 h and amplitude of
0.74 mag. The 12-hour solution is almost exactly 1.5 times the
period found by three different observers using lightcurve
photometry analysis. This may indicate a miscount of the number
of rotations over the time of the data in either the Hanus et al.
(2015) or our solution.
4272 Entsuji. This is a binary MBA discovered in 1977. The
satellite was discovered by Benishek et al. (2015). They reported a
primary rotation period of 2.8087 h and the satellite’s orbital
period as 15.94 hours, which is also probably its rotation period.
They estimated the effective diameter ratio of the two bodies to be
Ds/Dp = 0.18.
The analysis of our data from 2015 September shows a rotation
period of 2.81 ± 0.01 h, which is consistent with the results from
Benishek et al. (2015). The lightcurve amplitude is 0.06
magnitudes. We did not see any signs of the satellite because of the
short time we observed the asteroid.
10907 Savalle. There were no previous entries in the LCDB
(Warner et al., 2009) for this main-belt asteroid that was
discovered in 1997. Our bimodal lightcurve with an amplitude of
only 0.07 mag indicates a rotation period of 6.08 hours. The low
amplitude could be caused by viewing the asteroid nearly pole-on
or it being nearly spheroidal in shape. The large scatter in the data
made the analysis difficult. Future observations are encouraged.
6350 Schluter. This MBA was discovered in 1960. Tedesco et al.
(2004) found a diameter of 24.6 km and albedo of 0.0671. There
were no entries in the LCDB for Schulter. We observed the
asteroid for three nights in 2015 October and November. The
resulting lightcurve has a bimodal shape and period of 13.190 ±
0.001 h and maximum amplitude of 0.31 mag.
181
Acknowledgements
We would like to express our gratitude to Brian Warner for
supporting the CALL web site and his suggestions made to OBAS
group. We also thank Gary Vander Haarden for contributing his
data
References
Aznar. A. (2013). “Lightcurve of 3422 Reid using star subtraction
techniques.” Minor Planet Bull. 40, 214-215.
Barucci, M.A., Capria, M.T., Harris, A.W., Fulchignoni, M.
(1989). “On the shape and albedo variegation of asteroids - Results
from Fourier analysis of synthetic and observed asteroid
lightcurves.” Icarus 78, 311-322.
Behrend, R. (2004, 2005, 2006, 2007, 2011, 2015). Observatoire
de Geneve web site.
Benishek, V., Pollock, J., Hawkings, R., Pravec, P., Pray, D.,
Chiorny, V., Reichart, D., Haislip, J., Smith, A. (2015). “(4272)
Entsuji.” CBET 4158.
Klinglesmith III, D.A., Hendrickx, S., Madden, K., Montgomery,
S. (2016). “Lightcurves for Shape/Spin Models).” Minor Planet
Bull. 43, 124-129.
Oey, J. (2006). “Lightcurves analysis of 10 asteroids from Leura
Observator.” Minor Planet Bull. 33, 96-99.
Pligge, Z., Monnier, A., Pharo, J., Stolze, K., Yim, A., Ditteon, R.
(2011). “Asteroid Lightcurve Analysis at the Oakley Southern Sky
Observatory: 2010 May.” Minor Planet Bull. 38, 5-7.
Pollock, J., Caton, D., Hawkings, R., Pravec, P., Pray, D., Cooney,
W., Gross, J., Terrell, D., Oey, J., Benishek, V., Galad, A., Gajdos,
S., Groom, R., Stranger, K., Chiorny, V,. Reichart, D., Haislip, J.,
Smith, A. (2015). “(2343) Siding Spring.” CBET 4206.
Pozzoli, V. (2003). Posting on CALL web site.
http://www.MinorPlanet.info/call.html
Pray, D.P., Pravec, P., Marchini, A., Salvaggio, F., Papini, R.,
Pollock, J., Caton, D., Hawkins, R., Benishek, V., Smith, A.,
Reigchart, D., Haislip, J. (2015). “(3433) Fehrenbach.” CBET
4201.
Binzel, R.P. (1987). “A photoelectric survey of 130 asteroids.”
Icarus 72, 135-208.
Tedesco, E.F., Noah, P.V., Price, S.D. (2004). “IRAS Minor Planet
Survey.” IRAS-A-FPA-3-RDR-IMPS-V6.0. NASA Planetary Data
System.
Brinsfield, J.W. (2010). “Asteroid Lightcurve Analysis at the Via
Capote Observatory: 2009 3rd Quarter.” Minor Planet Bull. 37, 1920.
Vander Haagen, G.A. (2008). “Lightcurves of Minor Planets 2118
Flagstaff (15161) 2000 FQ48, and (46436) 2002 LH5.” Minor
Planet Bull. 35, 49.
Carbo, L., Kragh, K., Krotz, J., Meiers, A., Shaffer, N., Torno, S.,
Sauppe, J., Ditteon, R. (2009). “Asteroid lightcurve analysis at the
Oakley Southern Sky Observatory: 2008 September and October.”
Warner, B.D. (2006). Asteroid lightcurve analysis at the Palmer
Divide Observatory: March-June 2006.” Minor Planet Bull. 33,
85-88.
Casalnuovo, G.B. (2016). “Lightcurve Analysis for Nine Main-belt
Asteroids.” Minor Planet Bull. 43, 112-115.
lightcurve database.” Icarus 202, 134-146. Updates available at
Chang, C.-K., Ip, W.-H., Lin, H.-W., Cheng, Y.-C., Ngeow, C.-C.,
Yang, T.-C., Waszczak, A., Kulkarni, S.R., Levitan, D., Sesar, B.,
Laher, R., Surace, J., Prince, T.A. (2014). “313 New Asteroid
Rotation Periods from Palomar Transient Factory Observations.”
Ap. J. 788, A17.
Chiorny V., Galad, A., Pravec, P., Kusnirak, P., Hornoch, K.,
Gajdos, S., Kornos, L., Vilagi, J., Jusarik, M., Kanuchova, Z., and
9 coauthors. (2011). “Absolute photometry of small main- belt
asteroid in 2007-2009.” Planetary and Space Science 51, 14821489.
150, A75.
Zappala, V., Cellini, A., Barucci, A.M., Fulchignoni, M.,
Lupishko, D.E. (1990). “An analysis of the amplitude-phase
relationship among asteroids.” Astron. Astrophys. 231, 548-560.
Fauerbach, M., Marks, S.A., Lucas, M.P. (2008). “Lightcurve
Analysis of Ten Main-belt Asteroids.” Minor Planet Bull. 35, 4446.
444 Gyptis.” Icarus 57, 251-258.
Hanus, J., Durech, J., Oszkiewicz, D.A., Behrend, R., Carry, B.,
Delbo, M., Adam, O., Afonina, V., Anquetin, R., Antonini, P., and
159 coauthors. (2015). “New and updated convex shape models of
asteroids based on optical data from a large collaboration
network.” Astron. Astrophys., in press. arXiv:1510.07422.
182
ROTATION PERIOD, COLOR INDICES, AND H-G
PARAMETERS FOR 49 PALES
Frederick Pilcher
Las Cruces, NM 88011-8403 USA
[email protected]
Vladimir Benishek
Daniel A. Klinglesmith III
Etscorn Campus Observatory (719)
New Mexico Tech
101 East Road
Socorro, NM USA 87801
For 49 Pales a synodic rotation period 20.704 ± 0.001
hours and an amplitude 0.17 ± 0.01 magnitudes are
found. This is double the period found in the LCDB and
shows that correct rotation periods still have not been
found for all low-numbered asteroids. Color indices are
found <B-V> = 0.71± 0.02, <V-R> = 0.35 ± 0.03 and
<B-R> = 1.07 ± 0.05. In the V band H = 7.61 ± 0.06,
G = 0.019 ± 0.030.
Authors Pilcher, Benishek, and Klinglesmith agreed to collaborate
to make photometric observations of this low-numbered asteroid
when it became apparent that the previously believed rotation
period was not correct. Pilcher at Organ Mesa Observatory used a
0.35 m f/10 Meade LX200 GPS S-C, SBIG STL-1001E CCD,
unguided, R filter. Benishek at Sopot Observatory used a 0.35 m
SCT operating at f/6.3, SBIG ST-8 XME CCD. Klinglesmith at
Etscorn Campus Observatory used a Celestron 35 cm SCT and
SBIG STL-1001E CCD. Photometric measurement, lightcurve
analysis, and data sharing were enabled by MPO Canopus
software. The large number of data points obtained have been
binned in sets of three with time difference not exceeding five
minutes to draw the lightcurves.
No lightcurves have been published for 49 Pales since 1979. In
that year two rotation periods were published by Schober et al.
(1979), 10.42 hours; and by Tedesco (1979), 10.3 hours.
Seventeen all night sessions were made by the three authors 2015
Oct. 27 – Dec. 16 and provide a fit to a somewhat irregular
lightcurve with period 20.704 ± 0.001 hours and amplitude 0.17 ±
0.01 magnitudes. A few apparent deviations from the lightcurve
are quite likely observational artifacts (often beginning- or end-ofsession features) and not a real behavior of the asteroid. The
20.704 hour period is twice the value found in the much less dense
earlier investigations, and a period near 10.4 hours may now be
ruled out.
Color indices and H-G parameters determination
In order to determine the B-V, V-R and B-R color indices,
Benishek at Sopot Observatory conducted multi-color photometric
observations using the Johnson B and V and Cousins R
photometric filters on 9 nights between 2015 November 17 and
2015 December 30. The V-band photometry was omitted over the
first three of these nine nights. The Comparison Star Selector
procedure of MPO Canopus was used to perform the photometric
reduction process implying differential photometry using field
comparison stars of near solar color (0.5 ≤ B-V ≤ 0.9). The
instrumental magnitudes were calibrated using the Johnson B and
V magnitudes taken directly from the AAVSO Photometric AllSky Survey (APASS) catalog, Data Release 9 (Henden et al.,
2009) and the Cousins R magnitudes derived from the APASS
Johnson B and V magnitudes using the following catalog
independent conversion formula based on the LONEOS (Lowell
Observatory
Near-Earth-Object
Search)
Johnson-Cousins
photometry for faint field stars (Seiichi Yoshida's Home Page,
2016): R = V - 0.508 * (B - V) - 0.040, which is applicable under
the following condition: 0.3 < B-V < 0.9. This condition is
certainly fulfilled for the comparison stars of near solar color as
defined in MPO Canopus (see the aforementioned criterion).
The color indices were determined for each night separately from
the data sets obtained in the corresponding photometric filters. The
relevant differences in magnitude between the data taken with
different filters were found by shifting the zero point of one of the
data sets from the respective pair to bring them up to the best
match in terms of the minimum RMS error. The amount of this
shift determines a color index value for a particular night. The
summary of the color index values found for particular nights is
shown in the Table 1. There is a considerable consistency of the
corresponding color index values within the limits which do not
exceed a few hundredths of magnitude. The average values with
the related standard deviations for all three color indices calculated
from the corresponding values for the individual nights are as
follows: <B-V> = 0.71 ± 0.02 mag., <V-R> = 0.35 ± 0.03 mag.
and <B-R> = 1.07 ± 0.05 mag. Having in mind that 49 Pales has
been already classified as an CG Tholen spectral type asteroid
(JPL, 2016), it can also be stated that our values found for the B-V
and V-R color indices are well matched with the corresponding
average color indices typical for the C-type asteroids as shown in
Shevchenko and Lupishko (1998).
Date and mid-time (UT)
2015 Nov. 17.1
2015 Nov. 17.9
2015 Nov. 19.9
2015 Dec. 13.7
2015 Dec. 14.8
2015 Dec. 17.8
2015 Dec. 27.8
2015 Dec. 28.9
2015 Dec. 30.9
B-V
/
/
/
0.736
0.674
0.703
0.706
0.710
0.712
V-R
/
/
/
0.409
0.344
0.353
0.335
0.324
0.342
B-R
1.129
1.079
1.085
1.145
1.017
1.057
1.041
1.034
1.055
Table 1. Color indices for particular nights
Using the spreadsheet method described by Buchheim (2010) the
R-band mean light values of the lightcurves for individual nights
for the overall data obtained by all authors using an R photometric
filter were calculated. These were converted into reduced
magnitudes by applying -5*log(rΔ) with r and Δ being,
respectively, the asteroid-Sun and asteroid-Earth distances. The Rband reduced magnitudes obtained in such a way were used in the
H-G Calculator tool of MPO Canopus based on the FAZ algorithm
developed by Alan Harris (1989) to establish the phase curve and
determine the R-band absolute magnitude HR and slope parameter
G. Our analysis found the following pair of values: HR = 7.256 ±
0.028 and G = 0.019 ± 0.030. The V-band absolute magnitude Hv
= 7.61 ± 0.06 was calculated by adding the value found for V-R
color index to the R-band absolute magnitude HR. This enables the
estimation of the asteroid size using the formula by Pravec and
Harris (2007) for an asteroid diameter (D) in kilometers:
183
D( km ) =
1329
Pv
10 −0.2 H v
Assuming the value for the geometric albedo of 0.0597 (JPL,
2016) we obtain an estimated diameter of nearly 168 km for 49
Pales. This€is a somewhat larger value than that found by IRAS:
149.8 km (JPL, 2016). In either case, the values obtained for the
color indices and slope parameter G as well as the estimated size
indicate that 49 Pales is a fairly large and dark asteroid.
Acknowledgments
The Etscorn Campus Observatory operations are supported by the
Researach and Economic Development Office of New Mexico
Institute of Mining and Technology (NMIMT). The authors thank
Dr. Petr Pravec for help in the data analysis and interpretation.
References
Buchheim, R.K. (2010). “Methods and Lessons Learned
Determining the H-G Parameters of Asteroid Phase Curves.” in
Proceedings for 29th Annual Symposium on Telescope Science. pp.
101-115. Society for Astronomical Sciences. Rancho
Cucamonga,CA.
Fig. 1. Rotational lightcurve of 49 Pales phased to 20.704 hours.
Harris, A.W. (1989). “The H-G Asteroid Magnitude System: Mean
Slope Parameters.” Abstracts of the Lunar and Planetary Science
Conference 20, 375.
Henden, A.A., Terrell, D., Levine, S.E., Templeton, M., Smith,
T.C., Welch, D.L. (2009). “The AAVSO Photometric AllSkySurvey (APASS).” https://www.aavso.org/apass
JPL (2016). Small-Body Database Browser - JPL Solar System
Dynamics web site. http://ssd.jpl.nasa.gov/sbdb.cgi
Pravec, P., Harris, A.W. (2007). "Binary Asteroid Population I.
Angular Momentum Content." Icarus 158, 106-145.
Schober, H.J., Scaltriti, F., Zappala, V. (1979). “Photoelectric
photometry and rotation periods of three large and dark asteroids 49 Pales, 88 Thisbe, and 92 Undina.” Astron. Astrophys. Suppl.
Ser. 36, 1-8.
Figure 2. B, V, and R lightcurves obtained on particular nights for
color indices determination
Seiichi Yoshida's Home Page. Magnitude System and Color
Conversion Formulas (2016).
http://www.aerith.net/astro/color_conversion.html
Shevchenko, V.G., Lupishko, D.F. (1998). “Optical properties of
Asteroids from Photometric Data.” Solar System Research 32, 220232.
Tedesco, E.F. (1979)
University, 280 pp.
Ph. D. dissertation, New Mexico State
Figure 3. The phase curve of 49 Pales
184
6384 KERVIN:
A POSSIBLE HUNGARIA BINARY ASTEROID
magnitudes and the upper case M to catalog (apparent) magnitudes.
For a measurement on a given image, the asteroid’s apparent
magnitude was computed by finding the average of up to five
values using Eq. 1 (once for each comp star). No first or second
order extinction or color term corrections were applied. Ignoring
the last two may have increased the standard deviation of the mean
for each observation, but it was less than by using non-solar color
comparison stars.
Brian D. Warner
Center for Solar System Studies–Palmer Divide Station
446 Sycamore Ave.
Eaton, CO 80615 USA
[email protected]
Amadeo Aznar Macías
IAO-Isaac Aznar Observatory. MPC-Z95
Centro Astronómico del Alto Turia
46179 Aras de los Olmos, Valencia SPAIN
The initial observations from mid-December to mid-January by
Warner found a unique period using the FALC algorithm by Harris
(Harris et al., 1989) but the resulting lightcurve appeared to have a
low amplitude secondary component. The dual period search
function in MPO Canopus (which uses the FALC algorithm as
well) led to a preliminary result of about 12 or 24 hours for the
secondary period.
Analysis of CCD photometric observations in late 2015
of the Hungaria asteroid 6384 Kervin indicates that it
may be a binary asteroid with a primary lightcurve of
P1 = 3.6194 ± 0.0001 h, A1 = 0.06 ± 0.01 mag. The
secondary lightcurve parameters are P2 = 15.94 ± 0.01 h,
A2 = 0.03 ± 0.01 mag. No mutual events (occultations or
eclipses) were observed. However, other indicators give
an estimated diameter ratio on the order of Ds/Dp ~ 0.3,
possibly greater.
Since this was commensurate with an Earth day, additional
observations were requested of Aznar since his data would cover
parts of the long period not covered by the CS3 data. It took only
one observing run from Spain to remove the ambiguities and find a
period of almost 16 hours for the long period, which is also
commensurate with an Earth day. The value of combining data
from well-separated longitudes was demonstrated once again.
CCD photometric observations of the Hungaria asteroid 6384
Kervin were made from 2015 Dec 16 thru 2016 Jan 13. The
equipment and observing circumstances are given in Tables I and
II.
OBS
Telescope
Camera
Warner
Macías
0.30-m f/9.6 SCT
0.35-m f/10 SCT
FLI ML-1001E
SBIG STL-1001E
Obs
Warner
Macías
2015/16
mm/dd
12/16
01/13
01/13
Sess
α
1-13
15
14
5.2
21.1
21.1
LPAB
77
77
BPAB
+1
+7
7
Table II. Dates of observation for each observer. a is the solar phase
angle at the earliest and latest observation. The last two columns
are the average or extreme phase angle bisector longitude and
latitude (see Harris et al., 1984).
The asteroid had been observed at four previous apparitions by
Warner (2006; 2008; 2011; 2014) as part of an on-going study of
the Hungarias centering on rotational and binary statistics as well
as pole axis orientations. The previous results all found a period of
about 3.62 hours and no reported indications of a satellite, save in
2006 when some signs were seen but ultimately rejected.
The 2015 observations were unfiltered. Both authors used MPO
Canopus to measure the images. The Comp Star Selector utility in
MPO Canopus allowed choosing up to five near solar-color stars to
minimize color difference problems. The raw instrumental
magnitudes were referenced to V magnitudes from the APASS
catalog (Henden et al., 2009) using the simple formula
Mt = (mt – mc) + Mc
(1)
where the subscripts t and c refer to the asteroid and a comparison
star, respectively. The lower case m refers to instrumental
The two lightcurves show the final results. The primary lightcurve
has a period of 3.6194 ± 0.0001 h and amplitude of 0.06 ± 0.01
mag. It does not have a simple bimodal shape, which is entirely
possible for objects of low amplitude seen at low phase angles (see
Harris et al., 2014). The secondary lightcurve has a period of 15.94
± 0.01 h and amplitude of 0.03 ± 0.01 mag. Despite this low
amplitude, the lightcurve has a well-defined bimodal shape. This is
185
often an indicator of a nearly spheroidal satellite with its rotation
period tidally-locked to the orbital period. No signs of mutual
events (occultations or eclipses) were seen.
data. Some well-coordinated and prolonged campaigns in the
future may find those mutual events or at least help confirm the
periods reported here.
From here, we quote the analysis of Alan Harris (private
communications):
If nothing else, this case reinforces the idea that when observing a
small asteroid (D < 10 km) with a period in the range of 2-4 hours,
it should be followed for a number of nights, preferably including
extended blocks of contiguous nights. As happened here, it took
observations covering nearly a month to find a reliable solution.
Keep in mind that because the range of reasonable orbital periods
for a binary system includes several that are nearly commensurate
with an Earth day, help from one or more additional stations may
be required.
… the fact that there are no mutual events implies that you
are viewing from off the equatorial plane by a significant
amount, hence amplitudes are muted compared to equatorial
aspect. Further, you do still see curvature in the secondary
lightcurve, indicating that the lightcurve of the secondary is
substantial. Assuming the “undiluted” amplitude is no
greater than ~1 mag, then the light of the secondary must be
at least ~5% of the total light, which implies that it must be
~1/4 the diameter of the primary. It can’t plausibly be much
smaller, as that would imply an even larger undiluted
amplitude (recall you are viewing off the equator), so I would
infer a rather largish secondary. The 16 h period
corresponds to a fairly close-in binary separation (around 4
primary radii).
… the short period, with four extrema, looks like it has a
significant first harmonic in the solution, and maybe even
other odd harmonics. That would argue additionally for a
non-equatorial aspect, although if it is only a first harmonic,
that could be albedo variegation.
The terms of the fourth-order Fourier model bear this out. The
magnitudes of the third order terms are greater than those for the
second order while the first and fourth orders have maximum terms
of almost identical magnitude.
Taking a Second Look
A check of the previous results shows that the amplitude of the
primary lightcurve has ranged from 0.06 to 0.16 mag, implying
that the primary also has a nearly spheroidal shape. The lowest
amplitude, in 2008, was matched in 2015. The two apparitions
occurred at a similar phase angle bisector longitude (LPAB; see
Harris et al., 1984). The LPAB at other apparitions were
significantly different. The 2015 results raised the question of
whether or not evidence of a satellite had been overlooked in the
earlier analysis.
The data from Warner for the four previous apparitions were
reanalyzed using a narrow dual period search centered on the
primary and secondary periods found in 2015. The 2006 data
showed some indications of the secondary lightcurve, but it was
less well-defined than in 2015. This may have been due in part to
the data set not being as complete and so the forced secondary
lightcurve was poorly or not covered over a span of about 3 hours
(about 20% of the period).
We note that Warner et al. (2006) reported signs of a secondary
period that were eventually rejected. The scatter (noise) in that data
set was considerably greater than in 2015. The other data sets were
also hampered by having fewer data points and so it was difficult
to find a convincing solution for the secondary period.
Acknowledgements
The authors thank Alan Harris for his evaluation of the lightcurves.
Aznar expresses his gratitude to Brian Warner for the invitation to
participate in the 6384 Kervin analysis and would like to give
special thanks to Alan Harris for sharing his knowledge in minor
planets. Funding for Warner was provided by NASA grant
NNX13AP56G. This research was made possible through the use
of the AAVSO Photometric All-Sky Survey (APASS), funded by
the Robert Martin Ayers Sciences Fund.
References
444 Gyptis.” Icarus 57, 251-258.
3, 24, 60, 261, and 863.” Icarus 77, 171-186.
T.C., Welch, D.L. (2009). http://www.aavso.org/apass
Warner, B.D., Pray, D.P., Pravec, P. (2006). “The lightcurve of
Hungaria asteroid 6384 Kervin.” Minor Planet Bull. 33, 99.
Divide Observatory: December 2007 - March 2008.” Minor Planet
Bull. 35, 95-98.
Divide Observatory: 2010 December- 2011 March.” Minor Planet
Bull. 38, 142-149.
Warner, Brian D. (2014). “Asteroid Lightcurve Analysis at CS3Palmer Divide Station: 2014 March-June.” Minor Planet Bull. 41,
235-241.
Conclusion
We propose that 6384 Kervin is a binary asteroid with, possibly, a
significantly-sized satellite. It appears that mutual events are not
easily observed since a range of phase bisector longitudes did not
reveal any events nor cause a noticeable change in the secondary
lightcurve, other than to make it to disappear into the noise in the
186
ROTATIONAL PERIOD DETERMINATION OF
2717 TELLERVO AND (9773) 1993 MG1
Maurizio Scardella, Angelo Tomassini, Francesco Franceschini
ATA (Associazione Tuscolana di Astronomia)
F. Fuligni Observatory (MPC code D06)
Via Lazio, 14 - Rocca di Papa (RM) - 00040 – ITALY
[email protected]
observations were carried out from F. Fuligni Observatory and by
Francesco Franceschini during four nights in 2015 July. Our
analysis found a bimodal lightcurve with a synodic period of
P = 2.67 ± 0.01 h and amplitude of A = 0.24 mag.
The main-belt asteroids 2717 Tellervo and (9773)
1993 MG1 were observed over several nights throughout
2015 May-August in order to determine their synodic
rotational periods.
CCD photometric observations of the main-belt asteroids 2717
Tellervo and (9773) 1993 MG1 were made on several nights in
2015 from May to August in order to determine their rotation
periods and lightcurve amplitudes.
Observations at the F. Fuligni Observatory were made using a
0.35-m f/10 Meade ACF telescope and SBIG ST8-XE CCD
camera with Bessel R filter. Franceschini used a 0.230m f/6.3
reflector telescope equipped with Atik 314L- CCD camera and
Astrodon R filter. All images were dark and flat-field calibrated
with Maxim DL. Differential photometry and period analysis were
done using MPO Canopus (Warner, 2012).
2717 Tellervo. This main-belt asteroid was observed before by our
team (Tomassini et al., 2013). At that time, we found a bimodal
lightcurve with a period of 8.428 h and amplitude of 0.40 mag. Our
more recent data were obtained on five nights from 2015 May to
June. Analysis of the new data set found a period P = 4.213 ±
0.001 hours and amplitude 0.40 mag. The period is almost exactly
one-half the one we found in 2012.
The 2012 data had a much smaller number of data points that were
obtained over a period of almost two months. The 2015 data set
has many more data points that were obtained over a shorter
period. We believe the shorter period is more likely the right one.
References
Tomassini, A., Scardella, M., La Caprara, G. (2013). Lightcurve of
2717 Tellervo.” Minor Planet Bull. 40, 108-109.
10.4.1.9. Bdw Publishing, http://minorplanetobserver.com/
Warner, B.D. (2015). “Lightcurve Photometry Opportunities: JulySept 2015.” Minor Planet Bull. 42, 228-232.
PHOTOMETRIC OBSERVATIONS AND LIGHTCURVE
ANALYSIS FOR ASTEROIDS 782 MONTEFIORE,
(294739) 2008 CM, AND (303142) 2004 DU24
Vladimir Benishek
[email protected]
Analysis of photometric observations carried out from
2015 October-December found the synodic rotation
periods and lightcurve amplitudes for three minor
planets: 782 Montefiore, (294739) 2008 CM, and
(303142) 2004 DU24. The V-R color index for (294739)
2008 CM was found to be V-R = 0.52 ± 0.05 mag.
Photometric observations of three asteroids were carried out from
2015 October through December at the Sopot Astronomical
Observatory (SAO) using a 0.35-m f/6.3 Schmidt-Cassegrain
(SCT) equipped with a SBIG ST-8XME CCD camera. Johnson V
and Cousins R photometric filters were used in the case of the
near-Earth asteroid (294739) 2008 CM. The exposures were
unfiltered for the other asteroids. The camera was operated in a
2x2 binning mode, which produced an image scale of 1.66
arcsec/pixel. Prior to measurements, all images were corrected
using dark and flat field frames.
(9773) 1993 MG1. Discovered in June 1993 by E.F. Helin at
Mount Palomar Observatory, this main-belt asteroid was selected
from the one of the regular “Photometry Opportunities” lists given
by Warner et al. (2015) in the Minor Planet Bulletin. The
187
Photometric reduction, lightcurve construction, and period analysis
were conducted using MPO Canopus (Warner, 2015). Differential
photometry with up to five comparison stars of near solar color
(0.5 ≤ B-V ≤ 0.9) was performed using the Comparison Star
Selector (CSS) utility. This helped ensure a satisfactory quality
level of night-to-night zero point calibrations and correlation of the
measurements within the standard magnitude framework.
To calibrate field comparison stars, the Johnson V magnitudes
from the AAVSO Photometric All-Sky Survey catalog (APASS;
Henden et al., 2009), Data Release 9 were used for unfiltered and
V-band filter photometry. For the comparison stars on the frames
obtained with a Cousins R filter, the calibration was done using the
Johnson B and V APASS magnitudes and applying the conversion
formula (Yoshida, 2016)
R = V – 0.508 * (B–V) – 0.040
(1)
which is based on the LONEOS (Lowell Observatory Near-EarthObject Search) Johnson-Cousins photometry for faint field stars.
The formula is applicable for a range of 0.3 < B-V < 0.9, which is
fulfilled for the MPO Canopus near solar color stars. In some
instances, small zero point adjustments were necessary in order to
achieve the best match between individual data sets in terms of
minimum RMS residual of a Fourier fit.
782 Montefiore. Although several rotation period determinations
have been done before for this main-belt asteroid (4.08 h,
Wisniewski et al., 1997; 4.0730 h, Behrend 2007; 4.07 h, Galad
2008; 4.0728 h, Han et al., 2013; 4.076 h, Schmidt 2015), it was
nevertheless selected as a relatively bright target suitable to be
observed in less than favorable photometric conditions. The
observations were carried out over a single night, on 2015 Oct. 31 Nov. 1 UT, for almost 7 hours. The observing session resulted in
124 data points that covered almost two rotations. Analysis of the
data found a bimodal lightcurve with a period of 4.069 ±
0.008 h and amplitude of 0.54 mag.
The data were collected by alternating between Johnson V and
Cousins R filters throughout each night. Accordingly, for any
particular field, two separate data sets in two photometric bands
were obtained.
The overall lightcurve did not change significantly from night-tonight. To find the period, the combined data from both nights and
both photometric bands were combined into a single data set. The
resulting lightcurve has an unambiguous period of
P = 3.075 ± 0.003 h and amplitude of A = 0.18 mag. For clarity,
the data points in the lightcurve are binned in sets of 2 with a
maximum time difference of 5 minutes between the 2 data points.
It should be noted that this lightcurve has a more complex shape
and substantially lower amplitude than the lightcurve obtained by
Warner during the January 2014 apparition that had an amplitude
of 0.48 mag. This can be attributed to the substantially changed
viewing geometry. Nevertheless, a high degree of consistency
between the periods found at the two apparitions is obvious.
(294739) 2008 CM. Warner (2014) reported a period of 3.054 h for
this Apollo-type near-Earth asteroid (NEA). As a favorable radar
target (the closest approach was within 0.058 AU on 2015 Dec 29)
it was scheduled for radar observations at Arecibo and Goldstone
between 2015 Dec 27 and 31. As an NEA target of interest, it was
observed at SAO during two consecutive nights, 2015 Dec 25-26
and 26-27 UT. Due to the rapid apparent motion of the asteroid in
a relatively small CCD field of view, the data from each night were
divided into a number of subsets, each based on a different set of
comparison stars.
The two-color data were used to determine a color index for the
asteroid by averaging the individual values found for each
matching pair of V and R data sets. Based on the data from the two
nights, the result was V-R = 0.52 ± 0.05 mag.
188
Observations of 782 Montefiore, 3842 Harlansmith 5542 Moffatt,
6720 Gifu, and (19979) 1989 VJ.” Minor Planet Bull. 40, 99-100.
T.C., Welch, D.L. (2009). “The AAVSO Photometric All-Sky
Survey (APASS).” https://www.aavso.org/apass
Schmidt, R.E. (2015). “NIR Minor Planet Photometry from
Burleith Observatory: 2014 February - June.” Minor Planet Bull.
42, 1-3.
Bull. 41, 157-168.
Warner, B.D. (2015). Bdw Publishing MPO Software, MPO
Canopus version 10.7.0.1.
(303142) 2004 DU24. No previously reported rotation period was
found for this Mars-crosser.
Wisniewski, W.Z., Michalowski, T.M., Harris, A.W., McMillan,
R.S. (1997). “Photoelectric Observations of 125 Asteroids.” Icarus
126, 395-449.
Yoshida, S. (2016). “Magnitude System and Color Conversion
Formulas.”
http://www.aerith.net/astro/color_conversion.html
ROTATION PERIOD DETERMINATION
FOR 5401 MINAMIODA
Alessandro Marchini
Via Roma 56, 53100 - Siena, ITALY
[email protected]
Lorenzo Franco
Riccardo Papini
Spedaletto, Florence, ITALY
The asteroid had a favorable opposition on 2015 October 22 when
it reached an apparent magnitude of V~15.4. Photometric
observations were carried out SAO from 2015 Oct. 2-31, which
resulted in three independent data sets with a total of 222 data
points. Period analysis found a bimodal lightcurve a period of
P = 6.2501 ± 0.0002 h. The amplitude, A = 0.73 mag, and the low
phase angles puts a bimodal solution beyond any doubt (Harris et
al., 2014).
References
http://obswww.unige.ch/~behrend/page4cou.html
Galad, A. (2008). “Several Byproduct Targets of Photometric
Observations at Modra.” Minor Planet Bull. 35, 17-21.
Han, X.L, Li, B., Zhao, H., Liu, W., Sun, L., Shi, J., Gao, S.,
Wang, S., Pan, X., Jiang, P., Zhou, H. (2013). “Photometric
Fabio Salvaggio
21047 - Saronno, ITALY
Photometric observations of the main-belt asteroid 5401
Minamioda in 2015 November revealed a monomodal
lightcurve phased to 3.949 ± 0.001 hours as the more
likely solution for the synodic rotation period of the
asteroid, although a bimodal solution phased to 7.897 ±
0.003 hours cannot be ruled out completely.
5401 Minamioda (1989 EV) is a main-belt asteroid discovered at
Minami-Oda on 1989 March 6 by T. Nomura and K. Kawanishi. It
is named for the Minami-Oda district of Hyogo Prefecture in Japan
where the residents cooperated in establishing an observatory in
1971 (MPC 22509). The asteroid orbits with a semi-major axis of
about 2.797 AU, eccentricity 0.149, and a period of 4.68 years. Its
absolute magnitude is 12.1 (JPL, 2015; MPC, 2015). WISE
infrared radiometry reports an estimated diameter of D = 10.076 ±
0.136 km based on an optical albedo of 0.333 ± 0.057 and H =
11.80 ± 0.15 (Masiero et al., 2011). Using photometric sparse data
from the Catalina Sky Survey (MPC 703; CSS, 2015), we derived
189
H = 12.32 ± 0.07 and G = 0.38 ± 0.09 (Fig. 1), which is close to
those from the JPL Small-Body Database Browser. Xu et al.
(1995) and Bus and Binzel (2002) found that 5401 Minamioda
belongs to taxonomic class S.
The period analysis yielded two possible solutions that clearly
stand out in the period spectrum (RMS vs. period; Fig. 2). The
stronger solution near 3.9 hours corresponds to a monomodal
lightcurve while the secondary solution at about 7.8 hours features
a bimodal lightcurve. One way to resolve the ambiguity between
the two periods is to use what is called a “split halves plot”, as
outlined by Harris et al. (2014).
Figure 1. HG plot for 5401 Minamioda from 703 Catalina Sky Survey
photometric sparse data.
A search of the asteroid lightcurve database (LCDB; Warner et al.,
2009) indicates that our work might be the first reported lightcurve
observations and results for this object. The asteroid was reported
as a lightcurve photometry opportunity for 2015 November in the
Minor Planet Bulletin (Warner et al., 2015).
Observations at the Astronomical Observatory of the University of
Siena were carried out on five nights from 2015 November 1-8
using a 0.30-m f/5.6 Maksutov-Cassegrain telescope, SBIG STL6303E CCD camera, and clear filter; the pixel scale was 2.26
arcsec in binning 2x2 with 300 seconds exposure time for all
images. A total of 343 data points were collected. Over the interval
of about 8 days, the phase angle ranged from 5.9 to 2.1 degrees
before opposition.
Images were calibrated with bias, flat, and dark frames. Data
processing, including reduction to R band, and period analysis
were performed using MPO Canopus (BDW Publishing, 2012).
Differential photometry measurements were performed using the
Comp Star Selector (CSS) utility in MPO Canopus that allows
selecting up to five comparison stars of near solar color.
Subsequently, additional adjustments of the magnitude zero-points
for the particular data sets were carried out in order to find the
minimum RMS value from the Fourier analysis.
Figure 3. The split halves plot for 5401 Minamioda.
Here (Fig. 3), the period (P) for the bimodal solution is used, but
the data are plotted using the half-period (P/2) corresponding to the
period of the monomodal solution. This results in the second half
of the lightcurve overlaying the first half. In the split halves plot,
open black circles represent data from 0.0 to 0.5 rotation phase of
the full period and red stars represent data from 0.5 to 1.0 rotation
phase. The two halves are similar, meaning that there is a
possibility that the half-period is the correct solution.
If the two halves had diverged significantly, the half-period would
have been ruled out or, at least, that it was much less likely to be
the correct period. Therefore, we concluded that the most likely
synodic period for 5401 Minamioda is associated with the
monomodal lightcurve phased to 3.949 ± 0.001 hours with an
amplitude of 0.11 ± 0.03 mag (Fig. 4), although the bimodal
solution phased to 7.897 ± 0.003 hours with an amplitude of 0.10 ±
0.03 mag (Fig. 5) cannot be ruled out completely. Observations at
future oppositions will be required to increase the confidence in the
period.
Figure 2. The period spectrum for 5401 Minamioda.
190
MPC (2015). MPC Database.
http://www.minorplanetcenter.net/db_search/
lightcurve database.” Icarus 202, 134-146. Updated 2015
December 7. http://www.minorplanet.info/lightcurvedatabase.html
Warner, B.D. (2012). MPO Software, MPO Canopus v10.4.1.9.
Bdw Publishing. http://minorplanetobserver.com
Warner, B.D., Harris, A.W., Ďurech, J., Benner, L.A.M. (2015).
“Lightcurve photometry opportunities: 2015 October-December.”
MPB 42, 286-290.
Xu, S., Binzel, R.P., Burbine, T.H., Bus, S.J. (1995). “Small MainBelt Asteroid Spectroscopic Survey: Initial results.” Icarus 115, 1–
35.
Figure 4. The lightcurve for 5401 Minamioda phased to the period of
the monomodal solution (3.949 h).
Figure 5. The lightcurve for 5401 Minamioda phased to the period of
the bimodal solution (7.897 h).
References
Bus, S.J., Binzel, R.P. (2002). “Phase II of the Small Main-Belt
Asteroid Spectroscopic Survey.” Icarus 158, 146-177.
CSS (2015). Catalina Sky Survey web site.
http://www.lpl.arizona.edu/css/
CORRIGENDUM
MPB VOLUME 43, PAGE 23
Stephens, R.D., Warner, B.D. (2016). “Lightcurve Observations of
(348400) 2005 JF21: an NEA Binary.” Minor Planet Bulletin 43,
22-24.
The formula for finding the effective diameter ratio of a satellite to
D s D p ≥ 1 − 10 −0.4 Δm
its primary in a binary asteroid system was given incorrectly as
€ Hahn (1997; Icarus 127, 431-440) give the correct
Pravec and
formula as
D s D p ≥ 10 0.4 Δm − 1
JPL (2015). Small-Body Database Browser.
Dailey, J., Eisenhardt, P.R.M., McMillan, R.S., Spahr, T.B.,
Skrutskie, M.F., Tholen, D., Walker, R.G., Wright, E.L., DeBaun,
E., Elsbury, D., Gautier, T., IV, Gomillion, S., Wilkins, A. (2011).
“Main Belt Asteroids with WISE/NEOWISE. I. Preliminary
Albedos and Diameters.” Astrophys. J. 741, A68.
The estimated value of Ds/Dp ≥ 0.19 ± 0.02 given in the paper did
not change since the two formulae give very similar results when
€
Δm < 0.1 mag.
The ≥ symbol indicates that a total mutual event was not seen and
so the value represents a minimum. If there had been a total event,
then the formula would give the actual ratio.
191
TARGET ASTEROIDS! OBSERVING CAMPAIGNS FOR
APRIL THROUGH JUNE 2016
Carl Hergenrother and Dolores Hill
Lunar & Planetary Laboratory
University of Arizona
1629 E. University Blvd.
Tucson, AZ 85721 USA
[email protected]
Asteroid campaigns to be conducted by the Target
Asteroids! program during the April-June 2016 quarter
are described. In addition to asteroids on the original
Target Asteroids! list of easily accessible spacecraft
targets, an effort has been made to identify other
asteroids that are 1) brighter and easier to observe for
small telescope users and 2) analogous to (101955)
Bennu and (162173) Ryugu, targets of the OSIRIS-REx
and Hayabusa-2 sample return missions.
Introduction
The Target Asteroids! program strives to engage telescope users of
all skill levels and telescope apertures to observe asteroids that are
viable targets for robotic sample return. The program also focuses
on the study of asteroids that are analogous to (101955) Bennu and
(162173) Ryugu, the target asteroids of the NASA OSIRIS-REx
and JAXA Hayabusa-2 sample return missions respectively. Most
target asteroids are near-Earth asteroids (NEA) though
observations of relevant main-belt asteroids (MBA) are also
requested. An overview of the Target Asteroids! program can be
found at Hergenrother and Hill (2013).
Even though many of the observable objects in this program are
faint, acquiring a large number of low S/N observations allows
many important parameters to be determined. For example, an
asteroid’s phase function can be measured by obtaining
photometry taken over a wide range of phase angles. The albedo
can be constrained from the phase angle observations, as there is a
direct correlation between phase function and albedo (Belskaya
and Shevchenko (2000). The absolute magnitude can be estimated
by extrapolating the phase function to a phase angle of 0°. By
combining the albedo and absolute magnitude, the size of the
object can be estimated.
Current Campaigns
Target Asteroids! continues to conduct a number of dedicated
campaigns on select NEAs and analog carbonaceous MBAs during
the quarter. These campaigns have a primary goal of conducting
photometric measurements over a large range of phase angles.
Target Asteroids! objects brighter than V = 17.0 are presented in
detail. A short summary of our knowledge of each asteroid and 10day (shorter intervals for objects that warrant it) ephemerides are
presented. The ephemerides include rough RA and Dec positions,
distance from the Sun in AU (r), distance from Earth in AU (Δ), V
magnitude, phase angle in degrees (PH) and elongation from the
Sun in degrees (Elong).
We ask observers with access to large telescopes to attempt
observations of spacecraft accessible asteroids that are between V
magnitude ~17.0 and ~20.0 during the quarter (contained in the
table below).
Asteroid
Number
(7350)
(163249)
(162173)
(173664)
(187040)
(307564)
(311925)
(382758)
(371660)
Name
1993 VA
2002 GT
Ryugu
2001 JU2
2005 JS108
2003 FQ6
2007 BF72
2003 GY
2007 CN26
2009 DN1
Peak V
Mag
15.8
18.5
19.3
17.7
19.5
19.1
18.5
17.8
19.8
19.6
Time of Peak
Brightness
early Apr
early Apr
late Jun
late Jun
mid May
late Jun
late Jun
mid May
late Apr
early Apr
The campaign targets are split up into two sections: carbonaceous
MBAs that are analogous to Bennu and Ryugu; and NEAs
analogous to the Bennu and Ryugu or provide an opportunity to fill
some of the gaps in our knowledge of these spacecraft targets
(examples include very low and high phase angle observations,
phase functions in different filters and color changes with phase
angle).
The ephemerides listed below are just for planning purposes. In
order to produce ephemerides for your observing location, date and
time, please use the Minor Planet Center’s Minor Planet and
Comet Ephemeris Service:
http://www.minorplanetcenter.net/iau/MPEph/MPEph.html
or the Target Asteroids! specific site created by Tomas Vorobjov
and Sergio Foglia of the International Astronomical Search
Collaboration (IASC) at
http://iasc.scibuff.com/osiris-rex.php
Analog Carbonaceous Main Belt Asteroid Campaigns
(207) Hedda (a=2.28 AU, e=0.03, i=3.8°, H = 9.9)
The target asteroids of the OSIRIS-REx and Hayabusa-2 missions
probably originated in the inner part of the main belt (between 2.0
and 2.55 AU) on low inclination orbits. Target Asteroids! is
conducting many campaigns on objects in this region of the belt.
Hedda is not a member of any of the known asteroid families in the
innermost main belt. It is a hydrated carbonaceous object with a Ch
taxonomy (Bus and Binzel 2002). It is dark (0.04-0.06 albedo)
with a diameter on order of ~60 km (Tedesco et al. 2002). Multiple
rotation periods have been determined at 12, 13.6 and 30.1 hours.
The relatively long rotation period and low amplitude (~0.1
magnitudes) are probably the reason for the difficulty in
determining a definitive period. Long sequences over the course of
many nights will help resolve the rotation period question.
Observations covering phase angles of 1.5° and 20.8° are possible
this quarter. Peak brightness occurs on May 17 at V = 12.3.
DATE
04/01
04/11
04/21
05/01
05/11
05/21
05/31
06/10
06/20
06/30
16
16
15
15
15
15
15
15
15
15
RA
04
02
58
50
40
29
19
11
06
04
DEC
-22 08
-22 29
-22 42
-22 46
-22 39
-22 23
-22 03
-21 42
-21 27
-21 21
∆
1.46
1.37
1.30
1.24
1.22
1.21
1.23
1.28
1.34
1.42
r
2.22
2.22
2.22
2.22
2.22
2.22
2.22
2.22
2.22
2.23
V
13.5
13.3
13.0
12.7
12.4
12.3
12.7
12.9
13.2
13.4
PH Elong
21 128
18 138
14 149
9 160
4 172
3 174
8 163
13 152
17 141
20 131
192
Near-Earth Asteroid Campaign Targets
(7350) 1993 VA (a=1.36 AU, e=0.39, i=7.3°, H = 17.1)
Carbonaceous and located on a low delta-V orbit, (7350) 1993 VA
would make a nice future spacecraft target. Typical of a
carbonaceous C-type asteroid, 1993 VA has a very dark albedo of
0.05 (Thomas et al. 2014, Mainzer et al. 2011). Little is known of
its rotational properties and this apparition will be a prime
opportunity to determine its rotational period. Peak brightness
occurred back in late March/early April at V = 15.8. It can be
observed over phase angles of 40° to 71° during the period when it
is brighter than V = 18.
DATE
04/01
04/11
04/21
05/01
05/11
05/21
RA
08 35
10 39
11 32
12 02
12 22
12 39
DEC
+58 21
+47 22
+36 40
+28 24
+21 56
+16 39
∆
0.17
0.21
0.27
0.34
0.43
0.52
r
1.04
1.10
1.17
1.23
1.29
1.35
V
15.8
15.9
16.4
16.9
17.4
17.9
PH Elong
71 100
56 114
48 121
43 123
41 120
40 117
(35396) 1997 XF11 (a=1.44 AU, e=0.48, i=4.1°, H = 16.9)
This asteroid burst onto the world’s ‘radar’ back on March 11,
1998 when it was found that it could pass extremely close to Earth
on October 26, 2028 (Marsden 1998). Additional observations
have refined its orbit and we now know it will pass 2.4 lunar
distance from Earth on that date.
XF11 is Xk or K type asteroid with a rotation period of 3.26 h and
high amplitude of up to 1 magnitude (Binzel et al. 2004, Slivan et
al. 2003). Minimum phase angle will happen on April 13 at 2.1°
and V = 15.7. Observations up to a phase angle of 120° are
possible while it is brighter than V = 18. Color photometry over a
large range of phase angles will determine if XF11 experiences
phase angle dependent color changes.
DATE
04/01
04/11
04/21
05/01
05/11
05/21
05/31
06/10
13
13
12
12
11
11
10
09
RA
40
24
59
27
50
09
21
19
DEC
-14 24
-12 06
-08 19
-02 51
+04 04
+11 54
+20 21
+28 54
∆
0.47
0.38
0.31
0.26
0.23
0.20
0.19
0.18
r
1.46
1.39
1.31
1.24
1.16
1.08
1.00
0.92
V
16.8
15.8
15.7
15.7
15.7
15.9
16.4
17.5
compositional assessment of near-Earth object mission targets.”
Meteorit. Planet. Sci. 39, 351-366.
Bus, S.J., Binzel, R.P. (2002). “Phase II of the small main-belt
asteroid spectroscopic survey: a feature-based taxonomy”. Icarus
158 146-177.
Hergenrother, C., Hill, D. (2013). “The OSIRIS-REx Target
Asteroids! Project: A Small Telescope Initiative to Characterize
Potential Spacecraft Mission Target Asteroids.” Minor Planet
Bulletin 40, 164-166.
Mainzer, A. et al. (2011). “NEOWISE Observations of Near-Earth
Objects: Preliminary Results.” ApJ 743, 156.
Marsden, B.G. (1998). “1997 XF11”. IAUC 6837.
Slivan, S.M., Bowsher, E.C., Chang, B.W. (2003). “Rotation
period and spin direction of near-Earth asteroid (35396) 1997
XF11.” Minor Planet Bulletin 30, 29-30..
Tedesco, E.F., Noah, P.V., Noah, M., Price, S.D. (2002). “The
supplemental IRAS Minor Planet Survey”. Astronomical Journal
123, 1056-1085.
Thomas, C.A., Emery, J.P., Trilling, D.E., Delbo, M., Hora, J.L.,
Mueller, M. (2014). “Physical characterization of Warm Spitzerobserved near-Earth objects.” Icarus 228, 217-246.
PH Elong
12 163
3 176
11 166
27 147
45 126
66 104
89
80
116
55
(331471) 1984 QY1 (a=2.50 AU, e=0.89, i=14.3°, H = 15.4)
Little is known of this near-Earth asteroid. It becomes brighter than
V = 18 on May 20 while also rapidly moving away from the Sun.
Its phase angle decreases from 128° on May 20 to 38° at the end of
July. Peak brightness at V = 15.4 on June 6. Photometry of all
types is encouraged to determine this object’s taxonomy, rotation
period and phase angles.
DATE
05/21
05/31
06/10
06/20
06/30
04
11
14
14
15
RA
58
14
15
48
04
DEC
+56 52
+72 01
+42 21
+23 09
+12 36
∆
0.34
0.28
0.35
0.50
0.68
r
0.78
0.97
1.14
1.31
1.46
V
17.8
15.8
15.5
16.2
16.9
PH Elong
125
39
92
72
60 103
45 115
38 117
References
Belskaya, I., Shevchenko, V. (2000). “The Opposition Effect of
Asteroids.” Icarus 147, 94-105.
Binzel, R.P., Perozzi, E., Rivkin, A.S., Rossi, A., Harris, A.W.,
Bus, S.J., Valsecchi, G.B., Slivan, S. (2004). “Dynamical and
193
LIGHTCURVE PHOTOMETRY OPPORTUNITIES:
2016 APRIL-JUNE
Brian D. Warner
Center for Solar System Studies / MoreData!
446 Sycamore Ave.
Eaton, CO 80615 USA
[email protected]
Alan W. Harris
MoreData!
La Cañada, CA 91011-3364 USA
Josef Ďurech
Astronomical Institute
Charles University in Prague
18000 Prague, CZECH REPUBLIC
[email protected]
Lance A.M. Benner
Jet Propulsion Laboratory
Pasadena, CA 91109-8099 USA
[email protected]
We present lists of asteroid photometry opportunities for
objects reaching a favorable apparition and have no or
poorly-defined lightcurve parameters. Additional data on
these objects will help with shape and spin axis modeling
via lightcurve inversion. We also include lists of objects
that will be the target of radar observations. Lightcurves
for these objects can help constrain pole solutions and/or
remove rotation period ambiguities that might not come
from using radar data alone.
We present several lists of asteroids that are prime targets for
photometry during the period 2016 April-June.
In the first three sets of tables, “Dec” is the declination and “U” is
the quality code of the lightcurve. See the asteroid lightcurve data
base (LCDB; Warner et al., 2009) documentation for an
explanation of the U code:
The ephemeris generator on the CALL web site allows you to
create custom lists for objects reaching V ≤ 18.5 during any month
in the current year, e.g., limiting the results by magnitude and
declination.
http://www.minorplanet.info/PHP/call_OppLCDBQuery.php
We refer you to past articles, e.g., Minor Planet Bulletin 36, 188,
for more detailed discussions about the individual lists and points
of advice regarding observations for objects in each list.
Once you’ve obtained and analyzed your data, it’s important to
publish your results. Papers appearing in the Minor Planet Bulletin
are indexed in the Astrophysical Data System (ADS) and so can be
referenced by others in subsequent papers. It’s also important to
make the data available at least on a personal website or upon
request. We urge you to consider submitting your raw data to the
ALCDEF page on the Minor Planet Center web site:
We believe this to be the largest publicly available database of raw
lightcurve data that contains 2.5 million observations for more than
11400 objects.
Now that many backyard astronomers and small colleges have
access to larger telescopes, we have expanded the photometry
opportunities and spin axis lists to include asteroids reaching
V = 15.5.
In both of those lists, a line in italics text indicates a near-Earth
asteroid (NEA). In the spin axis list, a line in bold text indicates a
particularly favorable apparition. To keep the number of objects
manageable, the opportunities list includes only those objects
reaching a particularly favorable apparition, meaning they could all
be set in bold text.
Lightcurve/Photometry Opportunities
Objects with U = 3– or 3 are excluded from this list since they will
likely appear in the list below for shape and spin axis modeling.
Those asteroids rated U = 1 should be given higher priority over
those rated U = 2 or 2+, but not necessarily over those with no
period. On the other hand, do not overlook asteroids with U = 2/2+
on the assumption that the period is sufficiently established.
Regardless, do not let the existing period influence your analysis
since even high quality ratings have been proven wrong at times.
Note that the lightcurve amplitude in the tables could be more or
less than what’s given. Use the listing only as a guide.
Brightest
LCDB Data
Number Name
Date
Mag Dec Period
Amp
U
------------------------------------------------------------141354 2002 AJ29
04 03.8 15.0 -27
32219 2000 OU20
04 06.0 15.5 -11
7.172
0.18 2
12551 1998 QQ39
04 08.7 15.4 -9
15776 1993 KO
04 09.0 15.3 -7
6138 1991 JH1
04 09.2 15.4 -4
5.4566
0.37 2
11093 1994 HD
04 10.5 15.5 -3
1305 Pongola
04 11.6 14.3 -6
8.03
0.14-0.18 2
7084 1991 BR
04 16.3 15.5 -3
5.3075
0.19 2
6570 Tomohiro
04 19.1 15.3 -14
9.9653
0.51 2
21556 Christineli
04 21.6 15.2 -15
12.3704
0.12 2
5406 Jonjoseph
05 01.5 15.1 -18
3.5549
0.57 2
3159 Prokof'ev
05 06.4 14.8 -15
3.89
0.42 26056 Donatello
05 06.9 15.3 -16
6.2243
0.20 2
5135 Nibutani
05 09.8 15.0 -19
1179 Mally
05 10.0 15.3 -28
46.6917
0.08 1
8177 1992 BO
05 12.2 15.4 -23
6347 1995 BM4
05 15.4 15.4 -22
7.7392
0.35 2
1457 Ankara
05 16.1 13.5 -28
31.8
0.21 2
1259 Ogyalla
05 17.1 13.9 -18
17.3038 0.1-0.25 2
67681 2000 SH293
05 17.2 14.7 -21
19.8473
0.57 2
28461 2000 AL164
05 21.3 15.5 -20
3.44
0.09 1+
2307 Garuda
05 24.2 14.8 -23
29.64
0.32 2+
2332 Kalm
05 28.2 14.8 -24
22.8
0.39 2
1109 Tata
05 29.6 13.9 -24
8.277
0.06 2
3044 Saltykov
05 31.3 15.0 -19
0.04
9583 1990 HL1
05 31.5 15.5 -11
2584 Turkmenia
06 03.6 14.9 -23
6.3718
0.22 2
13846 1999 XV69
06 08.8 15.2 -22
50.9496
0.26 2
3353 Jarvis
06 09.1 14.6 -9 202.
0.10-0.50 2+
1108 Demeter
06 10.7 14.0 +1
9.7
0.12-0.15 2
6405 Komiyama
06 12.2 14.9 -17
19.855
0.13 2
8151 Andranada
06 12.7 14.5 -23
0.04
2259 Sofievka
06 15.6 13.7 -26
31.6
0.10 2
6135 Billowen
06 19.1 15.4 -32
28.4633
0.27 2
33719 1999 LA27
06 21.7 15.4 -20
11597 1995 KL1
06 22.2 15.3 -52
2415 Ganesa
06 22.9 15.2 -24
8.
0.15 2
31227 1998 BC41
06 24.0 14.7 -33
0.05
6003 1988 VO1
06 24.1 15.4 -15 104.4
0.07-0.42 2
6834 Hunfeld
06 24.6 15.3 -30
23268 2000 YD55
06 26.4 15.2 -20
3.3683
0.12 2
56785 2000 OS53
06 26.8 15.4 -23
1937 Locarno
06 29.0 13.6 -31
7945 Kreisau
06 29.0 15.4 -25
9245 1998 HF101
06 29.8 15.2 -19
http://www.minorplanetcenter.net/light_curve
194
Low Phase Angle Opportunities
Shape/Spin Modeling Opportunities
The Low Phase Angle list includes asteroids that reach very low
phase angles. The “α” column is the minimum solar phase angle
for the asteroid. Getting accurate, calibrated measurements
(usually V band) at or very near the day of opposition can provide
important information for those studying the “opposition effect.”
Use the on-line query form for the LCDB
Those doing work for modeling should contact Josef Ďurech at the
email address above. If looking to add lightcurves for objects with
existing models, visit the Database of Asteroid Models from
Inversion Techniques (DAMIT) web site
http://www.minorplanet.info/PHP/call_OppLCDBQuery.php
to get more details about a specific asteroid.
You will have the best chance of success working objects with low
amplitude and periods that allow covering at least half a cycle
every night. Objects with large amplitudes and/or long periods are
much more difficult for phase angle studies since, for proper
analysis, the data must be reduced to the average magnitude of the
asteroid for each night. This reduction requires that you determine
the period and the amplitude of the lightcurve; for long period
objects that can be difficult. Refer to Harris et al. (1989; Icarus
81, 365-374) for the details of the analysis procedure.
As an aside, some use the maximum light to find the phase slope
parameter (G). However, this can produce a significantly different
value for both H and G versus when using average light, which is
the method used for values listed by the Minor Planet Center.
The International Astronomical Union (IAU) has adopted a new
system, H-G12, introduced by Muinonen et al. (2010; Icarus 209,
542-555). However it will be some years before it becomes the
general standard and, furthermore, it is still in need of refinement.
That can be done mostly through having more data for more
asteroids, but only if there are data at very low and moderate phase
angles. Therefore, we strongly encourage observers to obtain data
for these objects not only at very low phase angles, but to follow
them well before and/or after opposition, i.e., out to phase angles
of 15-30 degrees.
Num Name
Date
α
V
Dec Period
Amp
U
------------------------------------------------------------834 Burnhamia
04 07.0 0.53 13.2 -05 13.875 0.15-0.22 3
186 Celuta
04 10.5 0.94 12.0 -10 19.842 0.4 -0.55 3
124 Alkeste
04 11.0 0.46 11.0 -07
9.921 0.08-0.15 3
3763 Qianxuesen
04 13.6 0.23 14.0 -09
3.884
0.31 3
205 Martha
04 14.9 0.68 13.0 -11 14.911 0.08-0.50 3
569 Misa
04 21.3 0.69 13.9 -14 13.52
0.25 2
1660 Wood
04 22.1 0.28 13.5 -13
6.809 0.14-0.26 3
378 Holmia
04 30.1 0.73 14.0 -17
4.450 0.11-0.21 3
1590 Tsiolkovskaja 05 03.5 0.33 13.2 -16
6.731 0.10-0.4 3
435 Ella
05 06.0 0.43 13.5 -18
4.623 0.30-0.45 3
76 Freia
05 07.2 0.31 13.0 -16
9.969 0.06-0.33 3
222 Lucia
05 08.4 0.65 12.7 -15
7.80 0.25-0.38 3
1259 Ogyalla
05 17.1 0.45 13.9 -18 12.
0.1 -0.3 1
447 Valentine
05 17.4 0.61 13.2 -18
9.651
0.18 3
425 Cornelia
05 20.0 0.08 13.1 -20 17.56
0.19 2
278 Paulina
05 20.5 0.28 12.1 -20
6.497
0.41 3
23 Thalia
05 22.9 0.51 10.4 -19 12.312 0.10-0.15 3
583 Klotilde
05 27.5 0.79 13.3 -24
9.212 0.18-0.41 2
384 Burdigala
05 27.7 0.91 13.7 -24 21.1
0.03 21109 Tata
05 29.6 0.74 13.9 -24
8.277
0.06 2
7 Iris
05 29.8 0.58 9.2 -23
7.139 0.04-0.29 3
277 Elvira
06 04.4 0.26 13.7 -22 29.69 0.34-0.59 3
274 Philagoria
06 07.4 0.59 13.4 -21 17.96 0.43-0.51 3
87 Sylvia
06 10.5 0.56 11.6 -25
5.184 0.22-0.62 3
90 Antiope
06 11.5 0.27 11.8 -24 16.509 0.08-0.90 3
505 Cava
06 18.0 0.30 13.1 -22
8.179 0.15-0.27 3
449 Hamburga
06 21.9 0.15 13.1 -24 18.263 0.08-0.17 2+
974 Lioba
06 25.2 0.44 13.5 -24 38.7
0.37 3
972 Cohnia
06 28.0 0.38 13.5 -24 18.472 0.19-0.21 3
http://astro.troja.mff.cuni.cz/projects/asteroids3D
An additional dense lightcurve, along with sparse data, could lead
to the asteroid being added to or improving one in DAMIT, thus
increasing the total number of asteroids with spin axis and shape
models.
Included in the list below are objects that:
1.
2.
Are rated U = 3– or 3 in the LCDB
Do not have reported pole in the LCDB Summary table
3.
Have at least three entries in the Details table of the
LCDB where the lightcurve is rated U ≥ 2.
The caveat for condition #3 is that no check was made to see if the
lightcurves are from the same apparition or if the phase angle
bisector longitudes differ significantly from the upcoming
apparition. The last check is often not possible because the LCDB
does not list the approximate date of observations for all details
records. Including that information is an on-going project.
Brightest
LCDB Data
Num
Name
Date
Mag Dec
Period
Amp
U
------------------------------------------------------------2573 Hannu Olavi
04 04.0 15.2 +7
4.9355 0.35-0.37 3
256 Walpurga
04 04.3 13.6 -2 16.664
0.36-0.41 3
937 Bethgea
04 04.4 14.7 -10
7.539
0.12-0.19 3
1369 Ostanina
04 04.4 15.1 -1
8.4001 0.73-1.11 3
834 Burnhamia
04 07.2 13.2 -5 13.875
0.15-0.22 3
750 Oskar
04 07.5 14.6 -2
6.2584 0.07-0.20 3
3223 Forsius
04 10.2 14.7 +0
2.343
0.20-0.22 3
124 Alkeste*
04 11.0 11.0 -7
9.921
0.08-0.15 3
205 Martha
04 14.9 13.0 -11 14.911
0.08-0.50 3
267 Tirza
04 15.7 13.6 -3
7.648
0.18- 0.4 3
2195 Tengstrom
04 15.8 15.4 -3
2.8211 0.17-0.45 3
2460 Mitlincoln
04 16.0 14.6 -7
3.01
0.03-0.20 3
456 Abnoba
04 18.0 11.9 -19 18.281
0.23-0.32 3
465 Alekto
04 18.0 12.8 -18 10.938
0.10-0.14 36495 1992 UB1
04 19.2 15.4 -18
5.693
0.29-0.45 3
78 Diana
04 19.5 11.3 -24
7.2991 0.02-0.30 3
1660 Wood
04 22.0 13.5 -13
6.809
0.14-0.26 3
545 Messalina
04 24.0 13.4 -26
7.2
0.27 3
1074 Beljawskya
04 25.0 15.0 -13
6.284
0.28-0.37 3
1248 Jugurtha
04 30.1 13.6 -6 12.91
0.70- 1.4 3
418 Alemannia
05 01.0 13.6 -20
4.671
0.14-0.33 3
524 Fidelio
05 02.9 14.0 -27 14.198
0.18-0.22 3
13166 1995 WU1
05 02.9 15.3 -15
3.8123 0.19-0.22 3
1590 Tsiolkovskaja 05 03.6 13.2 -16
6.731
0.10- 0.4 3
766 Moguntia
05 03.8 14.7 -24
4.8164 0.06-0.23 3
734 Benda
05 03.9 14.6 -21
7.11
0.28-0.32 3
3800 Karayusuf
05 04.6 15.5 +20
2.2319 0.15-0.19 3
1727 Mette
05 06.5 15.3 +24
2.9811 0.19-0.38 3
905 Universitas
05 07.1 14.6 -18 14.238
0.22-0.33 3
195 Eurykleia
05 07.6 13.0 -24 16.521
0.10-0.24 3
479 Caprera
05 08.4 14.6 -5
9.43
0.10-0.24 3
1764 Cogshall
05 09.1 14.8 -14
3.6242
0.21 3
3497 Innanen
05 09.9 14.9 +0
7.181
0.54-0.60 3
996 Hilaritas
05 10.0 14.9 -18 10.05
0.63-0.70 3
2114 Wallenquist
05 10.0 15.3 -18
5.51
0.22-0.30 3
194386 2001 VG5
05 10.3 14.5 -51
6.38
0.38- 0.7 3
1845 Helewalda
05 10.9 15.5 -3
7.2786 0.20-0.28 31344 Caubeta
05 13.0 14.4 -17
3.122
0.16-0.25 3
721 Tabora
05 13.7 14.7 -21
7.982
0.19-0.30 3
2653 Principia
05 16.9 15.0 -14
5.5228 0.34-0.50 3
239 Adrastea
05 17.1 15.4 -12 18.4707 0.34-0.51 3
2303 Retsina
05 18.6 15.4 +0 10.82
0.39-0.45 3
851 Zeissia
05 19.4 14.0 -16
9.34
0.38-0.53 3
1308 Halleria
05 19.5 14.8 -27
6.028
0.14-0.17 3
911 Agamemnon
05 20.3 15.4 -45
6.592
0.04-0.29 3
1547 Nele
05 20.4 15.4 -33
7.1
0.18-0.45 32121 Sevastopol
05 21.1 13.9 -11
2.9064 0.15-0.20 3
414 Liriope
05 22.4 14.8 -11
7.353
0.13 31509 Esclangona
05 24.4 14.6 -52
3.2528 0.11-0.35 3
4125 Lew Allen
05 25.8 15.1 -44
4.629
0.20-0.45 3
195
Brightest
LCDB Data
Num
Name
Date
Mag Dec
Period
Amp
U
------------------------------------------------------------1929 Kollaa
05 26.1 15.2 -21
2.9887 0.20-0.22 3
583 Klotilde
05 27.4 13.3 -24
9.2135 0.18-0.41 3
712 Boliviana
05 30.2 12.5 -16 11.7426 0.10-0.12 3
2141 Simferopol
06 02.1 14.8 -25 14.9508 0.30-0.48 3
1426 Riviera
06 05.8 13.4 -39
4.4044 0.30-0.31 3
656 Beagle
06 06.9 14.2 -22
7.035
0.85- 1.2 3
1127 Mimi
06 07.6 15.1 +15 12.749
0.72-0.95 3
554 Peraga
06 09.9 12.5 -26 13.7128 0.11-0.28 3
995 Sternberga
06 10.0 13.5 -10 14.612
0.12-0.20 3
3419 Guth
06 11.5 15.2 -34 14.43
0.15-0.29 3
1095 Tulipa
06 11.8 14.8 -8
2.7872 0.17-0.23 3
58 Concordia
06 13.0 12.4 -15
9.895
0.10-0.15 3
744 Aguntina
06 14.8 14.7 -14 17.47
0.50 3
4765 Wasserburg
06 16.4 15.4 -33
3.6231 0.04-0.60 3
651 Antikleia
06 18.7 14.6 -35 20.299
0.13-0.41 3
224 Oceana
06 19.6 11.9 -33
9.401
0.09-0.14 3
1222 Tina*
06 23.1 13.8 -7 13.395
0.18-0.30 3
126 Velleda
06 24.1 12.0 -28
5.3672 0.07-0.22 3
987 Wallia
06 24.5 13.2 -34 10.0813 0.11-0.36 3
1468 Zomba
06 25.3 14.1 -37
2.773
0.3-0.36 3
506 Marion
06 25.7 13.9 -39 13.546
0.17-0.35 3
11705 1998 GN7
06 27.2 15.4 -9
3.7187 0.32-0.45 3
1096 Reunerta
06 27.8 13.1 -28 13.036
0.26-0.39 3
972 Cohnia
06 28.1 13.5 -24 18.472
0.19-0.21 3
1254 Erfordia
06 29.6 14.8 -25 12.287
0.47 3
755 Quintilla
06 30.7 13.7 -18
4.552
0.08-0.45 3
Radar-Optical Opportunities
There are several resources to help plan observations in support of
radar.
Future radar targets:
http://echo.jpl.nasa.gov/~lance/future.radar.nea.periods.html
Past radar targets:
http://echo.jpl.nasa.gov/~lance/radar.nea.periods.html
and α is the phase angle. SE and ME are the great circles distances
(in degrees) of the Sun and Moon from the asteroid. MP is the
lunar phase and GB is the galactic latitude. “PHA” in the header
indicates that the object is a “potentially hazardous asteroid”,
meaning that at some (long distant) time, its orbit might take it
very close to Earth.
Some of the targets listed here may be carry-overs from the
previous quarter’s photometry opportunities article since they are
still reachable targets for at least part of the covered quarter-year.
About YORP Acceleration
Many, if not all, of the targets in this section are near-Earth
asteroids. These objects are particularly sensitive to YORP
acceleration. YORP (Yarkovsky–O'Keefe–Radzievskii–Paddack)
is the asymmetric thermal re-radiation of sunlight that can cause an
asteroid’s rotation period to increase or decrease. High precision
lightcurves at multiple apparitions can be used to model the
asteroid’s sidereal rotation period and see if it’s changing.
It usually takes four apparitions to have sufficient data to
determine if the asteroid is rotating under the influence of YORP,
so while obtaining a lightcurve at the current apparition may not
result in immediately seeing a change, the data are still critical in
reaching a final determination. This is why observing asteroids that
already have well-known periods can still be a valuable use of
telescope time. It is even more so when considering BYORP
(binary-YORP) among binary asteroids where that effect has
stabilized the spin so that acceleration of the primary body is not
the same as if it would be if there were no satellite.
Arecibo targets:
http://www.naic.edu/~pradar/sched.shtml
http://www.naic.edu/~pradar
Asteroid
Sisyphus
Goldstone targets:
http://echo.jpl.nasa.gov/asteroids/goldstone_asteroid_schedule.html
However, these are based on known targets at the time the list was
prepared. It is very common for newly discovered objects to move
up the list and become radar targets on short notice. We
recommend that you keep up with the latest discoveries using the
RSS feeds from the Minor Planet Center
http://www.minorplanetcenter.net/iau/rss/mpc_feeds.html
In particular, monitor the NEA feed and be flexible with your
observing program. In some cases, you may have only 1-3 days
when the asteroid is within reach of your equipment. Be sure to
keep in touch with the radar team (through Dr. Benner’s email
listed above) if you get data. The team may not always be
observing the target but, in some cases, your initial results may
change their plans. In all cases, your efforts are greatly
appreciated.
Use the ephemerides below as a guide to your best chances for
observing, but remember that photometry may be possible before
and/or after the ephemerides given below. Note that geocentric
positions are given. Use these web sites to generate updated and
topocentric positions:
MPC: http://www.minorplanetcenter.net/iau/MPEph/MPEph.html
JPL: http://ssd.jpl.nasa.gov/?horizons
In the ephemerides below, ED and SD are, respectively, the Earth
and Sun distances (AU), V is the estimated Johnson V magnitude,
Fam/Grp
NEA
Period
2.400
App
4
Last
2015
Bin
Y
1991 CS
NEA
2.389
3
2015
N
1997 XF11
NEA
3.259
1
2002
N
Apollo
NEA
3.065
6
2014
Y
2004 FG11
NEA
<4.
2
2014
Y
2008 TZ3
2009 KJ
NEA
NEA
-
-
-
-
2003 KO2
NEA
-
-
-
-
2009 DL46
NEA
-
-
-
-
2010 NY65
NEA
-
-
-
-
2002 KL6
NEA
4.610
1
2009
N
Table I. Summary of radar-optical opportunities in 2016 Apr-Jun.
Data from the asteroid lightcurve database (Warner et al., 2009;
Icarus 202, 134-146).
To help focus efforts in YORP detection, Table I gives a quick
summary of this quarter’s radar-optical targets. The Fam/Grp
column gives the family or group for the asteroid. The period is in
hours and, in the case of binary, for the primary. The App columns
gives the number of different apparitions at which a lightcurve
period was reported while the Last column gives the year for the
last reported period. The Bin column is ‘Y’ if the asteroid has one
or more satellites.
1866 Sisyphus (Apr-Jun, H = 13.0, Binary)
This is considered a known binary based on radar observations in
1985 (http://echo.jpl.nasa.gov/asteroids/Sisyphus/sisyphus.html)
that showed a spike in the echo power spectrum on several nights.
Stephens et al. (2011; MPB 38, 212-213) reported a possible
satellite with an orbital period of 25.5 h based on lightcurve
196
photometry. Assuming a binary, the primary has a period of about
2.40 h and amplitude that ranges from 0.01 to 0.15 mag.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------04/01 15 30.9 +19 53 1.82 2.60 16.7 16.6 132 66 -0.45 +53
04/11 15 19.7 +20 57 1.72 2.56 16.5 15.1 138 136 +0.19 +56
04/21 15 05.1 +21 38 1.65 2.52 16.3 14.1 142 38 +0.99 +59
05/01 14 48.1 +21 45 1.60 2.48 16.2 14.2 143 106 -0.40 +63
05/11 14 30.1 +21 10 1.58 2.44 16.2 15.6 140 99 +0.24 +67
05/21 14 12.8 +19 51 1.58 2.39 16.2 18.0 133 38 +0.99 +70
05/31 13 57.9 +17 54 1.61 2.34 16.3 20.8 125 147 -0.32 +72
06/10 13 46.1 +15 27 1.65 2.29 16.4 23.4 116 59 +0.29 +73
06/20 13 37.9 +12 39 1.72 2.24 16.5 25.6 107 67 +1.00 +72
06/30 13 33.3 +09 39 1.78 2.19 16.6 27.4 99 155 -0.24 +70
(7822) 1991 CS (Apr, H = 17.4, PHA)
The rotation period for this NEA is well-established at about
2.390 h. The period makes it an ideal candidate for being a binary,
even though the amplitude ranges from 0.26-0.39 mag. This makes
it more elongated than many known binary primaries, but there are
exceptions; this could be one as well.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------04/01 09 18.3 +53 25 0.47 1.23 18.1 50.7 108 137 -0.45 +43
04/02 09 19.9 +53 44 0.48 1.23 18.1 50.9 107 140 -0.35 +43
04/03 09 21.6 +54 01 0.49 1.23 18.2 51.1 107 139 -0.25 +43
04/04 09 23.3 +54 17 0.50 1.23 18.2 51.2 106 135 -0.16 +44
04/05 09 25.0 +54 31 0.51 1.24 18.3 51.4 105 128 -0.08 +44
04/06 09 26.8 +54 45 0.52 1.24 18.4 51.5 104 119 -0.03 +44
04/07 09 28.6 +54 57 0.53 1.24 18.4 51.6 104 109 +0.00 +44
04/08 09 30.5 +55 08 0.54 1.24 18.4 51.7 103 98 +0.01 +44
04/09 09 32.3 +55 18 0.55 1.24 18.5 51.8 102 87 +0.04 +45
04/10 09 34.2 +55 27 0.56 1.25 18.5 51.9 102 76 +0.10 +45
(35396) 1997 XF11 (Apr-May, H = 16.3, PHA)
The reported synodic periods for this NEA average about 3.257 h.
This is based on observations made by Pravec et al. in 2002. You
may recall that initial reports soon after its discovery concerning
the chances for the asteroid hitting the Earth in the not-to-distant
future eventually led to improvements in impact probability
monitoring.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------04/01 13 40.7 -14 24 0.47 1.45 16.8 11.8 163 79 -0.45 +47
04/08 13 29.9 -12 55 0.41 1.41 16.1
5.6 172 173 +0.01 +49
04/15 13 15.2 -10 46 0.35 1.35 15.6
3.5 175 75 +0.60 +52
04/22 12 56.4 -07 48 0.31 1.30 15.7 12.4 164 16 +1.00 +55
04/29 12 34.2 -04 02 0.27 1.25 15.7 23.4 150 107 -0.61 +59
05/06 12 09.0 +00 31 0.24 1.20 15.7 35.8 136 146 -0.01 +62
05/13 11 41.9 +05 38 0.22 1.14 15.8 49.4 121 39 +0.44 +63
05/20 11 13.1 +11 10 0.20 1.08 15.9 64.0 106 55 +0.97 +62
1862 Apollo (Apr-Jun, H = 16.3, PHA)
This is the namesake for the Apollo asteroids, those with orbits that
lie mostly outside Earth’s orbit but also cross it for a short time.
This is a binary, the satellite being discovered by Ostro et al.
(2005). The primary rotation period is 3.066 h. The amplitude of
the lightcurve changes dramatically from apparition to the next,
ranging from only 0.15 mag up to 1.15 mag. Apollo is one a small
number of asteroids where YORP acceleration has been confirmed
(Kaasalainen et al., 2007; Nature 446, 420-422). Additional
lightcurves can be used to confirm and improve the earlier results.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------04/01 19 42.5 -23 25 0.62 1.06 17.9 67.0 78
9 -0.45 -21
04/11 21 02.4 -20 41 0.59 0.97 17.8 76.0 69 120 +0.19 -38
04/21 22 21.8 -15 28 0.60 0.87 17.9 83.7 60 133 +0.99 -53
05/01 23 32.0 -08 57 0.67 0.78 18.1 87.5 51 28 -0.40 -64
05/11 00 31.4 -02 22 0.77 0.71 18.1 85.8 45 102 +0.24 -65
05/21 01 23.0 +03 44 0.90 0.66 18.0 78.8 40 149 +0.99 -58
05/31 02 10.4 +09 14 1.05 0.65 18.0 68.5 36 33 -0.32 -49
06/10 02 55.5 +13 59 1.20 0.67 18.0 57.6 34 98 +0.29 -39
06/20 03 38.8 +17 51 1.34 0.73 18.1 48.4 32 152 +1.00 -29
06/30 04 19.8 +20 47 1.47 0.81 18.4 41.6 32 27 -0.24 -20
(363599) 2004 FG11 (Apr, H = 20.9, PHA)
Radar observations by Taylor et al. (2012) found this to be a
binary with a satellite orbital period of 20.4 h. The primary period
is not well known, but is believed to be < 4 h. Lightcurve
observations in 2014 by Warner may have detected the satellite,
but only by forcing the data to the estimated orbital period. There
were no indications of the primary’s lightcurve at that time.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------04/01 14 43.8 +06 26 0.16 1.14 18.5 28.0 148 69 -0.46 +56
04/03 14 53.2 +09 35 0.13 1.11 18.2 30.4 146 93 -0.26 +56
04/05 15 07.3 +14 15 0.11 1.09 17.8 34.7 142 116 -0.09 +56
04/07 15 30.9 +21 35 0.08 1.06 17.4 42.6 134 132 +0.00 +53
04/09 16 17.6 +33 35 0.06 1.03 17.1 57.3 120 129 +0.04 +46
04/11 18 11.2 +49 47 0.05 1.01 17.4 82.8 94 110 +0.18 +27
04/13 21 38.7 +53 32 0.05 0.98 19.0 113.8 63 99 +0.38 +1
04/15 23 42.8 +42 58 0.07 0.95 21.4 136.2 41 107 +0.59 -18
(388945) 2008 TZ3 (Apr-May, H = 20.4)
This NEA has an estimated size of 250 meters. There are no
previous entries in the LCDB (Warner et al., Icarus 202, 134-146).
The size puts it on the cusp of being a super-fast rotator i.e., P < 2
h. Try as short of exposures as possible for the first hour or so and
then see what the preliminary analysis indicates. If possible and
required, increase the exposures to get a better SNR.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------04/05 14 30.8 +12 27 0.19 1.16 18.2 25.3 150 125 -0.09 +63
04/10 14 39.1 +11 46 0.15 1.14 17.8 25.0 151 149 +0.10 +60
04/15 14 49.9 +10 20 0.12 1.11 17.2 24.7 152 93 +0.59 +57
04/20 15 05.8 +07 35 0.09 1.09 16.6 24.2 154 41 +0.96 +53
04/25 15 32.6 +02 05 0.07 1.07 15.8 23.8 155 22 -0.93 +44
04/30 16 26.8 -09 54 0.05 1.05 15.0 27.7 151 62 -0.52 +26
05/05 18 39.0 -32 40 0.03 1.03 15.0 52.6 126 100 -0.05 -12
05/10 22 03.6 -42 52 0.04 1.01 16.5 85.3 92 127 +0.14 -53
05/15 23 50.9 -38 28 0.06 1.00 18.0 99.9 77 145 +0.63 -73
(406952) 2009 KJ (Apr-May, H = 17.1)
The period of 2009 KJ does not appear to have been determined.
Its estimated size is 1.1 km, so it’s likely that the period is greater
than 2 hours.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------04/18 08 01.3 -37 08 0.15 1.04 15.6 71.8 100 59 +0.85 -4
04/23 09 08.6 -35 25 0.23 1.10 16.2 58.5 110 78 -0.99 +8
04/28 09 42.7 -33 39 0.30 1.16 16.7 51.9 114 114 -0.72 +15
05/03 10 03.8 -32 20 0.38 1.22 17.3 48.1 116 139 -0.20 +18
05/08 10 18.8 -31 21 0.46 1.28 17.7 45.6 115 99 +0.02 +21
05/13 10 30.8 -30 38 0.55 1.33 18.1 43.9 114 49 +0.43 +23
05/18 10 41.1 -30 06 0.63 1.38 18.4 42.6 113 42 +0.87 +25
05/23 10 50.3 -29 43 0.71 1.43 18.8 41.6 111 83 -0.99 +26
2003 KO2 (Apr-May, H = 20.2, PHA)
The plan is for high-res imaging at Arecibo of this 270-meter
NEA. The lightcurve parameters have not been determined.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------04/25 06 27.0 -02 12 0.05 0.99 17.8 112.2 65 143 -0.93 -6
04/27 07 42.2 +09 47 0.05 1.00 17.2 98.2 79 154 -0.80 +16
04/29 08 43.3 +18 20 0.06 1.01 17.1 87.1 90 166 -0.62 +33
05/01 09 28.0 +23 26 0.07 1.02 17.3 79.9 96 168 -0.41 +44
05/03 10 00.0 +26 24 0.09 1.03 17.6 75.3 100 150 -0.20 +52
05/05 10 23.4 +28 10 0.10 1.04 17.9 72.4 102 127 -0.05 +57
05/07 10 40.9 +29 17 0.12 1.04 18.2 70.5 103 102 +0.00 +61
05/09 10 54.6 +30 00 0.14 1.05 18.4 69.2 103 77 +0.07 +64
05/11 11 05.5 +30 28 0.16 1.06 18.7 68.3 104 54 +0.23 +67
(154244) 2002 KL6 (May-Jul, H = 17.5)
The period for this 940 meter NEA was found to be about 4.61 h
during the last favorable apparition in 2009 (Galad et al., 2010,
MPB 37, 9-15; Koehn et al., 2014, MPB 41, 286-300). Be prepared
for a significant change in amplitude and/or shape as the asteroid
swings through a large range of phase angles. A good plan is to
observe the asteroid in short segments, e.g., 1-3 days, and treat
197
each one independently. This will allow following the changes in
in the lightcurve easier. It may be possible to get a sense of rotation
by noting if the period reaches a minimum (prograde) or maximum
(retrograde) at opposition. To make this a useful experiment, you’ll
need lightcurves well before and after opposition. Another point of
interest is that Thomas et al. (2014, Icarus 228, 217-246) classified
this as a type Q (between a V and S type). This is a very rare type
with one of the few known being 1862 Apollo.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------05/01 16 25.9 -19 01 0.52 1.49 17.9 17.9 153 74 -0.41 +21
05/11 16 30.7 -17 41 0.42 1.42 17.2 13.2 161 141 +0.23 +20
05/21 16 33.9 -15 40 0.34 1.35 16.4
8.2 169 19 +0.99 +21
05/31 16 36.3 -12 48 0.27 1.28 15.7
7.2 171 110 -0.33 +22
06/10 16 39.7 -08 44 0.21 1.22 15.3 13.6 164 107 +0.28 +24
06/20 16 47.7 -02 57 0.16 1.16 14.9 22.7 154 19 +1.00 +26
06/30 17 06.5 +05 46 0.12 1.11 14.5 32.8 144 138 -0.25 +26
07/10 17 50.5 +19 46 0.09 1.08 14.0 43.8 133 90 +0.31 +22
07/20 19 36.7 +39 06 0.07 1.05 13.9 56.7 120 56 -1.00 +9
07/30 22 35.6 +47 30 0.08 1.04 14.4 67.1 109 82 -0.18 -9
(444584) 2006 UK (May, H = 20.1, PHA)
This NEA has an estimated diameter of 280 meters, meaning its
rotation period is likely to be greater than ~2 hours.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------05/01 06 33.1 -18 56 0.05 0.99 17.8 109.1 68 126 -0.41 -12
05/05 09 41.6 -29 28 0.05 1.03 15.9 68.3 109 124 -0.05 +17
05/09 12 07.8 -26 00 0.07 1.06 15.9 39.3 138 109 +0.07 +36
05/13 13 10.8 -21 24 0.10 1.10 16.5 27.9 149 70 +0.43 +41
05/17 13 41.5 -18 34 0.13 1.13 17.1 23.9 153 28 +0.80 +43
05/21 13 59.5 -16 48 0.17 1.17 17.7 23.0 153 19 +0.99 +43
05/25 14 11.6 -15 41 0.21 1.20 18.2 23.3 152 64 -0.91 +43
05/29 14 20.5 -14 56 0.25 1.24 18.7 24.2 150 114 -0.56 +43
IN THIS ISSUE
This list gives those asteroids in this issue for
which physical observations (excluding
astrometric only) were made. This includes
lightcurves,
color
index,
and
H-G
determinations, etc. In some cases, no specific
results are reported due to a lack of or poor
quality data. The page number is for the first
page of the paper mentioning the asteroid. EP is
the “go to page” value in the electronic version.
Number
16
49
269
275
331
337
609
618
662
764
782
833
838
855
891
929
1001
1013
1016
1018
1084
1242
1343
1361
1466
1480
1511
1531
1531
Name
Psyche
Pales
Justitia
Sapientia
Etherridgea
Devosa
Fulvia
Elfriede
Newtonia
Gedania
Montefiore
Monica
Seraphina
Newcombia
Gunhild
Algunde
Gaussia
Tombecka
Anitra
Arnolda
Tamariwa
Zambesia
Nicole
Leuschneria
Mundleria
Aunus
Dalera
Hartmut
Hartmut
EP
27
72
25
25
25
19
25
64
64
64
76
1
64
13
61
13
64
64
19
64
44
64
64
2
44
64
2
11
64
Page
137
182
135
135
135
129
135
174
174
174
186
111
174
123
171
123
174
174
129
174
154
174
174
112
154
174
112
121
174
Number
1536
1614
1620
1654
1730
1967
2074
2104
2118
2136
2323
2343
2343
2379
2500
2616
2668
2717
2947
3000
3003
3285
3433
3606
3640
3682
3811
3873
3958
3987
4012
4055
4103
4145
4212
4272
4674
5087
5176
5186
5236
5240
5292
2009 DL46 (May-Jun, H = 21.6, PHA)
There are no entries in the LCDB for 2009 DL46, which has an
estimated effective diameter 140 meter. This makes it a potential
super-fast rotator (P < 2.1 h), so keep initial exposures as short as
possible. Given how bright it will be, this will be doublynecessary. Be careful about interference from the moon.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------05/15 11 49.7 +51 36 0.04 1.01 17.3 82.9 95 47 +0.63 +63
05/18 12 23.6 +44 18 0.03 1.02 16.4 76.4 102 49 +0.87 +72
05/21 13 12.0 +28 14 0.02 1.02 15.1 60.9 118 52 +0.99 +85
05/24 14 18.4 -05 38 0.01 1.03 13.7 29.3 150 53 -0.95 +51
05/27 15 38.0 -40 06 0.02 1.03 13.9 20.1 160 66 -0.76 +12
05/30 16 53.9 -55 30 0.03 1.04 15.1 33.2 146 87 -0.45 -7
06/02 17 52.5 -61 09 0.04 1.04 16.0 39.6 139 111 -0.14 -17
06/05 18 32.8 -63 18 0.05 1.05 16.7 42.2 136 131 +0.00 -22
(441987) 2010 NY65 (Jun-Jul, H = 21.5, PHA)
With an estimated diameter of 150 meters, this NEA is another
super-fast rotator candidate. The period is unknown.
DATE
RA
Dec
ED
SD
V
α
SE ME
MP
GB
------------------------------------------------------------06/25 11 59.1 +37 57 0.03 1.01 17.7 105.7 73 142 -0.79 +75
06/26 13 10.2 +35 54 0.03 1.01 17.2 92.3 86 137 -0.69 +80
06/27 14 04.9 +32 21 0.03 1.02 17.0 81.3 97 136 -0.59 +73
06/28 14 44.2 +28 37 0.04 1.03 17.0 72.7 105 137 -0.47 +65
06/29 15 12.2 +25 18 0.04 1.03 17.1 66.3 111 140 -0.36 +58
06/30 15 32.8 +22 32 0.05 1.04 17.3 61.4 116 144 -0.25 +53
07/01 15 48.3 +20 15 0.06 1.05 17.4 57.7 120 145 -0.16 +49
07/02 16 00.3 +18 22 0.06 1.05 17.6 54.8 122 144 -0.08 +46
07/03 16 09.8 +16 48 0.07 1.06 17.8 52.5 124 140 -0.03 +43
Name
Pielinen
Goldschmidt
Geographos
Bojeva
Marceline
Menzel
Shoemaker
Toronto
Flagstaff
Jugta
Zverev
Siding Spring
Siding Spring
Heiskanen
Alascattalo
Lesya
Tataria
Tellervo
Kippenhahn
Leonardo
Koncek
Ruth Wolfe
Fehrenbach
Pohjola
Gostin
Welther
Karma
Roddy
Komendantov
Wujek
Geballe
Magellan
Chahine
Maximova
Sansyu-Asuke
Entsuji
Pauling
Emel'yanov
Yoichi
Donalu
Yoko
Kwasan
1991 AJ1
EP
2
61
33
12
13
13
13
64
64
2
13
8
64
19
1
62
2
76
64
9
10
13
64
64
13
13
64
13
60
19
19
44
2
11
64
64
27
27
10
2
19
22
10
Page
112
171
143
122
123
123
123
174
174
112
123
118
174
129
111
172
112
186
174
119
120
123
174
174
123
123
174
123
170
129
129
154
112
121
174
174
137
137
120
112
129
132
120
Number
5401
5425
5595
5646
5806
6326
6350
6384
6454
6538
6611
6823
6853
7192
7958
9165
9465
9773
10064
10064
10565
10907
11054
11268
11268
11424
12614
13143
13762
14515
15520
16849
17447
20932
20936
20936
22977
23692
25638
28910
33342
36496
46989
Name
Minamioda
Vojtech
Roth
1990 TR
Archieroy
Idamiyoshi
Schluter
Kervin
1991 UG1
Muraviov
1993 VW
1988 ED1
Silvanomassaglia
Cieletespace
Leakey
Raup
1998 HJ121
1993 MG1
Hirosetamotsu
Hirosetamotsu
1994 AT1
Savalle
1991 FA
Spassky
Spassky
1999 LZ24
Hokusai
1995 AF
1998 SG130
Koichisato
1999 XK98
1997 YV
Heindl
2258 T-1
4835 T-1
Nemrut Dagi
1999 VF24
1997 KA
Ahissar
2000 NH11
1998 WT24
2000 QK49
1998 TO5
EP
18
55
10
33
48
22
64
74
10
22
33
13
50
22
56
27
22
76
2
64
10
64
33
2
31
13
22
22
22
2
22
22
27
48
27
27
22
22
22
62
33
27
22
Page
128
165
120
143
158
132
174
184
120
132
143
123
160
132
166
137
132
186
112
174
120
174
143
112
141
123
132
132
132
112
132
132
137
158
137
137
132
132
132
172
143
137
132
198
Number
48470
49669
52748
52748
53110
53115
53426
88263
112985
112985
135885
137084
138852
139515
152679
152978
155110
155110
155334
Name
1991
1999
1998
1998
1999
1999
1999
2001
2002
2002
2002
1998
2000
2001
1998
2000
2005
2005
2006
EP
48
27
22
48
33
27
33
33
33
50
27
33
33
27
33
33
33
50
33
TC2
RZ30
JJ1
JJ1
AR7
AM14
SL5
KQ1
RS28
RS28
TX49
XS16
WN10
PD53
KU2
GJ147
TB
TB
DZ169
Page
158
137
132
158
143
137
143
143
143
160
137
143
143
137
143
143
143
160
143
Number
159399
163000
163899
163899
194268
194386
200754
241339
241596
241804
249590
253106
253106
294739
294739
294739
303142
337866
442243
Name
1998
2001
2003
2003
2001
2001
2001
2007
1998
2001
1996
2002
2002
2008
2008
2008
2004
2001
2011
UL1
SW169
SD220
SD220
UY4
VG5
WA25
VL269
XM2
QW282
UG2
UR3
UR3
CM
CM
CM
DU24
WL15
MD11
EP
33
48
33
50
33
33
33
27
33
27
27
33
50
33
33
76
76
50
33
THE MINOR PLANET BULLETIN (ISSN 1052-8091) is the quarterly
journal of the Minor Planets Section of the Association of Lunar and
Planetary Observers (ALPO). Current and most recent issues of the MPB
are available on line, free of charge from:
http://www.minorplanet.info/mpbdownloads.html
Nonmembers are invited to join ALPO by communicating with: Matthew
L. Will, A.L.P.O. Membership Secretary, P.O. Box 13456, Springfield, IL
62791-3456 ([email protected]). The Minor Planets Section is directed
by its Coordinator, Prof. Frederick Pilcher, 4438 Organ Mesa Loop, Las
Cruces, NM 88011 USA ([email protected], assisted by Lawrence
Garrett, 206 River Rd., Fairfax, VT 05454 USA ([email protected]).
Dr. Alan W. Harris (Space Science Institute; [email protected]),
and Dr. Petr Pravec (Ondrejov Observatory; [email protected]) serve as
Scientific Advisors. The Asteroid Photometry Coordinator is Brian D.
Warner, Palmer Divide Observatory, 446 Sycamore Ave., Eaton, CO
80615 USA ([email protected]).
The Minor Planet Bulletin is edited by Professor Richard P. Binzel, MIT
54-410, Cambridge, MA 02139 USA ([email protected]). Brian D. Warner
(address above) is Assistant Editor. The MPB is produced by Dr. Robert A.
Werner,
3937
Blanche
St.,
Pasadena,
CA
91107
USA
([email protected]) and distributed by Derald D. Nye. Direct all
subscriptions, contributions, address changes, etc. to:
Mr. Derald D. Nye - Minor Planet Bulletin
10385 East Observatory Drive
Corona de Tucson, AZ 85641-2309 USA
([email protected]) (Telephone: 520-762-5504)
Effective with Volume 38, the Minor Planet Bulletin is a limited print
journal, where print subscriptions are available only to libraries and major
institutions for long-term archival purposes. In addition to the free
electronic download of the MPB noted above, electronic retrieval of all
Minor Planet Bulletin articles (back to Volume 1, Issue Number 1) is
available through the Astrophysical Data System
http://www.adsabs.harvard.edu/.
Authors should submit their manuscripts by electronic mail ([email protected]).
Author instructions and a Microsoft Word template document are available
at the web page given above. All materials must arrive by the deadline for
each issue. Visual photometry observations, positional observations, any
type of observation not covered above, and general information requests
should be sent to the Coordinator.
*
*
*
*
*
The deadline for the next issue (43-3) is April 15, 2016. The deadline for
issue 43-4 is July 15, 2016.
Page
143
158
143
160
143
143
143
137
143
137
137
143
160
143
143
186
186
160
143
Number
443837
450649
452302
Name
2000
2006
1995
2007
2009
2011
2011
2014
2015
2015
2015
2015
2015
2015
2015
2015
2015
2015
2015
TJ1
UY64
YR1
EA26
TK
WN15
YS62
EK24
FS332
SV2
SZ
TA25
TB145
VY105
WF13
WG9
XC
XC
XU378
EP
33
33
33
33
33
33
33
46
46
33
33
33
31
5
33
50
33
50
33
Page
143
143
143
143
143
143
143
156
156
143
143
143
141
115
143
160
143
160
143

MPB 43-2 revision 2

Transcription

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