PX437 EXOPLANETS

Cosmic abundance (by number)

Element Abundance

(per 100,000)

Common molecules

H 92,700 H2

(He) 7,200

O 50 H20

(Ne) 20

N 15 NH3

C 8 CH4

Si 2Mg2SiO4

Mg 2

Fe 1 Fe3O4

PX437 EXOPLANETS

Condensation by temperature

Condensation temperature

Materials Examples

1400-1700 KCa Al Ti

compoundsAl2O3 CaTiO3

refractory elements

common elements

1300-1400 K Mg, Si compounds

Mg2SiO4

MgSiO3

1350 K metallic iron alloys

Fe

370 K magnetite Fe3O4

180 K water ice H20volatile

Elements130 K ammonia

hydrateNH3·H20

40-80 K methane, methane ices

CH4

CH4·7H20

PX437 EXOPLANETS

Migration

PX437 EXOPLANETS

Elemental abundance (by number)

Universe

Element Abundance

(per 100,000)

H 92,700

(He) 7,200

O 50

(Ne) 20

N 15

C 8

Si 2

Mg 2

Fe 1

Human body

Element Abundance

(per 100,000)

H 60,563

O 25,670

C 10,680

N 2,440

Ca 230

P 130

S 130

PX437 EXOPLANETS

Carbon-silicate cycle and climate stabilisation

Walker et al. 1981

PX437 EXOPLANETSHabitable zones

PX437 EXOPLANETS

Earth spectrum

Selsis

PX437 EXOPLANETS

Detecting life?

Selsis 2007

PX437 EXOPLANETS

A search for life on Earth

Sagan et al, 1993, Nature 365, 715

PX437 EXOPLANETS

Vegetation Red Edge

Sagan et al, 1993, Nature 365, 715

PX437 EXOPLANETS

Earth transit transmission spectroscopy

Kaltenegger et al 2008

PX437 EXOPLANETSDarwin, ESA

PX437 EXOPLANETSDarwin, ESA