Galactic Chemical Evolution and the Emergence of Habitable Worlds

Galactic Chemical Evolution and the Emergence of Habitable Worlds

Galactic Chemical Evolution
and the
Emergence of Habitable Worlds
Eric Gaidos
University of Hawaii at Manoa
“I am a little world, made cunningly of elements....”
- John Donne
How many Earths?
Many Earth-size planets
Petigura et al. (2013)
26% of solar-type stars have 1-2 Earth-radius planets with P < 100 d
Comparative Cosmochemistry
< H2O/SiO2
< Mg/Fe
Earth-size planets in the “Habitable Zone”
Mann et al. (2013)
Transit of Venus on June 5, 2012
The First Hundred Million Years
Galactic timeline
13.80 +/- 0.04 Ga: it all begins
13+ Ga: oldest globular clusters
~12 Ga: oldest part of Bulge
9-10 Ga: Disk begins to be form
Prantzos (2007)
A Diversity in Production Ratio Dependencies
The “Galactic Habitable Zone”
Planets too large
Planets too small
Gonzalez et al. (2001)
“Galactic Habitable Zone” (again)
Lineweaver et al. (2004)
Galactic Habitable Zone (and again)
Prantzos (2007)
Planet-Metallicity Relation
Fischer & Valenti (2005)
Minimum Metallicity for Planet Formation
Johnson & Li (2012)
Theoretical Disk Surface Density – Planet Relation
Kokubo et al. (2006)
From Prantzos (2008) Based on Morbidelli (2007)
Stellar Metallicity Distribution and the “G Dwarf Problem”
Kobayashi et al. 2006
Kobayashi et al. 2006
Model predicts that oldest stars are very metal poor but also very few of these stars
Buchave et al. (2012)
M Dwarfs as Canaries of the Metallicity-Planet Relation
Williams & Cieza (2011)
Are Kepler M Dwarf Host Stars Preferentially Metal-Rich?
Schlaufman & Laughlin (2011)
A Giant Problem
7% giant star
contamination
96% giant star
contamination
The Metal-Rich Blues
Lepine et al.
Flux in r-band suppressed in metal-rich stars by molecular bands
Giant Stars Make the Reference Sample Have Bluer g-r Color
Schlaufman & Laughlin (2011)
Mann et al. (2012)
What about Neptune-size Planets?
Wang & Fischer (2013)
G1
K2
K7
M4
G7
M3
K4
M5
Metallicities of M dwarfs via FGK-type Companions
No metallicity-small planet relation for Kepler M dwarfs
Mann et al. (2013)
No Neptune-metallicity relation from Doppler surveys
Neves et al. (2013)
Evolution of the
Silicates to Iron Ratio
Edvardsson et al. (1993)
Si/Fe-Planet Correlation
Robinson et al. (2006)
van Summeren et al. (2013)
Al-26 and Wolf Rayet Stars
NGC 3603 (HST)
Gaidos et al. (2009)
Gilmour (2009)
Variation of C/O in Stars and Their Planet-Forming Disks
Based on Petigura & Marcy (2011)
High C/O
Low C/O
Carter-Bond et al. (2012)
Diffuse ISM
Infall
280 Myr
10 Myr
Bubbles
Star forming regions
Schmidt-Kennicut Law
Salpeter IMF
SN and
AGB ejecta
SN ejecta
Stars
Stellar remnants
Low-mass stars