CHEMISTRY OF SILICATE ATMOSPHERES OF EVAPORATING SUPER-EARTHS

By L. Schaefer, B. Fegley. 2009

140 citations recorded by the source corpus.

We model the formation of silicate atmospheres on hot volatile-free super-Earths. Our calculations assume that all volatile elements such as H, C, N, S, and Cl have been lost from the planet. We find that the atmospheres are composed primarily of Na, O2, O, and SiO gas, in order of decreasing abundance. The atmospheric composition may be altered by fractional vaporization, cloud condensation, photoionization, and reaction with any residual volatile elements remaining in the atmosphere. Cloud condensation reduces the abundance of all elements in the atmosphere except Na and K. We speculate that large Na and K clouds such as those observed around Mercury and Io may surround hot super-Earths. These clouds would occult much larger fractions of the parent star than a closely bound atmosphere, and may be observable through currently available methods.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/1aba693863aae6e6199363d573b6510ac3d9cb07

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In Astronomy and Astrophysics

Citations in the corpus

POSSIBLE DISINTEGRATING SHORT-PERIOD SUPER-MERCURY ORBITING KIC 12557548 (2012, background): “…melt is ρg ∼ P/c2s, where the surface pressure P ∼ 10 µbar at T = 2100 K, if the ocean is composed predominantly of Mg, Si, and O, with zero contribution from Na (see Figures 5 and 6 from Léger et al. 2011, and consider vaporized fractions 0.85 > Fvap > 0.02; see also Schaefer & Fegley 2009).”
Composition and fate of short-period super-Earths: The case of CoRoT-7b (2009, unknown): “Schaefer & Fegley (2009) find that the pressures decrease by about 1 order of magnitude when Na is lost, and then by a further 2 to 3 orders of magnitude at 90% of total erosion.”
Exoplanet Atmospheres: Physical Processes (2010, background): “The atmosphere would then be composed of silicates enriched in more refractory elements such as Ca, Al, Ti (Schaefer & Fegley 2009).”
How to Characterize Habitable Worlds and Signs of Life (2017, background): “They are, of course, not considered as habitable worlds, but assuming that their surface is molten at these extremely high stellar irradiances, their atmospheric makeup should showcase the material composition of the planet’s crust (see, e.g., Schaefer & Fegley 2009, Miguel et al. 2011).”
THREE POSSIBLE ORIGINS FOR THE GAS LAYER ON GJ 1214b (2009, background): “In addition, the conditions during magma solidification and outgassing affect the gas layer outcome (Elkins-Tanton & Seager 2008; Schaefer & Fegley 2009b).”