Chemistry of atmospheres formed during accretion of the Earth and other terrestrial planets

By L. Schaefer, B. Fegley. 2009

169 citations recorded by the source corpus.

Abstract We used chemical equilibrium and chemical kinetic calculations to model chemistry of the volatiles released by heating different types of carbonaceous, ordinary and enstatite chondritic material as a function of temperature and pressure. Our results predict the composition of atmospheres formed by outgassing during accretion of the Earth and other terrestrial planets. Outgassing of CI and CM carbonaceous chondritic material produces H 2 O-rich (steam) atmospheres in agreement with the results of impact experiments. However, outgassing of other types of chondritic material produces atmospheres dominated by other gases. Outgassing of ordinary ( H , L , LL ) and high iron enstatite ( EH ) chondritic material yields H 2 -rich atmospheres with CO and H 2 O being the second and third most abundant gases. Outgassing of low iron enstatite ( EL ) chondritic material gives a CO-rich atmosphere with H 2 , CO 2 , and H 2 O being the next most abundant gases. Outgassing of CV carbonaceous chondritic material gives a CO 2 -rich atmosphere with H 2 O being the second most abundant gas. Our results predict that the atmospheres formed during accretion of the Earth and Mars were probably H 2 -rich unless the accreted material was dominantly CI and CM carbonaceous chondritic material. We also predict significant amounts of S, P, Cl, F, Na, and K in accretionary atmospheres at high temperatures (1500–2500 K). Finally, our results may be useful for interpreting spectroscopic observations of accreting extrasolar terrestrial planets.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/8073397bbe3833e0727f69af9723462b0e03c578

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

PHOTOCHEMISTRY IN TERRESTRIAL EXOPLANET ATMOSPHERES. I. PHOTOCHEMISTRY MODEL AND BENCHMARK CASES (2012, background): “Super Earth atmospheres may originate from the capture of nebular gases, degassing during accretion, and/or degassing from subsequent tectonic activity (Elkins-Tanton & Seager 2008; Schaefer & Fegley 2010).”
FORMATION AND STRUCTURE OF LOW-DENSITY EXO-NEPTUNES (2011, background): “Third, heating of EH material releases a low mean molecular weight atmosphere; Schaefer & Fegley (2010) calculated 44% H2, 31% CO, 17% H2O, 5% CO2, and 3% other molecules by volume under their nominal conditions (1500 K, 100 bars).”
Exoplanet Atmospheres: Physical Processes (2010, background): “How much depends on the composition of planetesimals from which the planet formed (Elkins-Tanton & Seager 2008; Schaefer and Fegley 2010).”
Formation of planetary systems by pebble accretion and migration (2018, background): “This explains why the Earth does not have a primitive atmosphere, but instead one outgassed from its interior, dominated by much heavier gases than hydrogen (Schaefer & Fegley 2010).”
Origin and evolution of the atmospheres of early Venus, Earth and Mars (2018, background): “The early Hadean crustal and atmospheric conditions would have been more reducing compared to conditions during the Archean and later in Earth’s history, due to captured nebular gas, serpentinization and chemical equilibrium of the accreting chondritic material (Schaefer and Fegley 2010).”
Strange messenger: A new history of hydrogen on Earth, as told by Xenon (2018, background): “A more exotic possibility is that H2 and other reduced gases were injected episodically into the atmosphere from degassing of reduced impacting bodies (Kasting, 1990; Hashimoto et al., 2007; Schaefer and Fegley, 2010).”