Meteorite Outgassing Experiments to Inform Chemical Abundances of Super-Earth Atmospheres
Abstract
At present, there is no first principles understanding of how to connect a terrestrial planet's bulk composition to its atmospheric properties. Since terrestrial exoplanets likely form their atmospheres through degassing (Elkins-Tanton & Seager 2008), a logical first step to build such a theory for superEarths is to assay meteorites, the leftover building blocks of planets, by heating them to measure the outgassed volatiles. Our Solar System presents a wide variety of meteorite types, including chondrites which are primitive unaltered rocks believed to be representative of the material that formed the rocky planets. We present the current results of our meteorite outgassing experiments in which we heated a variety of chondritic meteorite samples, at carefully controlled rates to temperatures from 200 to 1200 °C and measured the partial pressures and relative abundances of the outgassed volatile species (e.g., CO2, H2O, CH4, H2, O2, S, Na) as a function of temperature and time. Our experimental setup consisted of a residual gas analyzer connected to a furnace to heat samples at specified rates. We compare the results of these experiments to Schaefer and Fegley's prior theoretical chemical equilibrium and kinetics calculations which modeled thermal outgassing for a wide variety of chondrites to predict the composition of terrestrial atmospheres formed via outgassing of specific types of meteorites (Schaefer & Fegley 2007, Schaefer & Fegley 2010). In addition to testing and validating Schaefer and Fegley's models, the results from our experiments inform the phase space of chemical abundances used in atmospheric models of superEarth exoplanets.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.P23B3487T
- Keywords:
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- 5210 Planetary atmospheres;
- clouds;
- and hazes;
- PLANETARY SCIENCES: ASTROBIOLOGY;
- 6207 Comparative planetology;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6296 Extra-solar planets;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 5405 Atmospheres;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS