Vaporization of the earth: application to exoplanet atmospheres.
SCHAEFER L., LODDERS K. and FEGLEY B.
Abstract (from CDS):
Currently, there are about three dozen known super-Earths (M < 10 M ⊕), of which eight are transiting planets suitable for atmospheric follow-up observations. Some of the planets are exposed to extreme temperatures as they orbit close to their host stars, e.g., CoRot-7b, and all of these planets have equilibrium temperatures significantly hotter than the Earth. Such planets can develop atmospheres through (partial) vaporization of their crustal and/or mantle silicates. We investigated the chemical equilibrium composition of such heated systems from 500 to 4000 K and total pressures from 10–6 to 10+2 bars. The major gases are H2 O and CO2over broad temperature and pressure ranges, and Na, K, O2, SiO, and O at high temperatures and low pressures. We discuss the differences in atmospheric composition arising from vaporization of SiO2-rich (i.e., felsic) silicates (like Earth's continental crust) and MgO-, FeO-rich (i.e., mafic) silicates (like the bulk silicate Earth). The computational results will be useful in planning spectroscopic studies of the atmospheres of Earth-like exoplanets.
astrochemistry - atmospheric effects - planets and satellites: general