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Losing oceans: The effects of composition on the thermal component of impact-driven atmospheric loss
- Source :
- Monthly Notices of the Royal Astronomical Society. 501:587-595
- Publication Year :
- 2020
- Publisher :
- Oxford University Press (OUP), 2020.
-
Abstract
- The formation of the solar system's terrestrial planets concluded with a period of giant impacts. Previous works examining the volatile loss caused by the impact shock in the moon-forming impact find atmospheric losses of at most 20-30 per cent and essentially no loss of oceans. However, giant impacts also result in thermal heating, which can lead to significant atmospheric escape via a Parker-type wind. Here we show that H2O and other high-mean molecular weight outgassed species can be efficiently lost through this thermal wind if present in a hydrogen-dominated atmosphere, substantially altering the final volatile inventory of terrestrial planets. Specifically, we demonstrate that a giant impact of a Mars-sized embryo with a proto-Earth can remove several Earth oceans' worth of H2O, and other heavier volatile species, together with a primordial hydrogen-dominated atmosphere. These results may offer an explanation for the observed depletion in Earth's light noble gas budget and for its depleted xenon inventory, which suggest that Earth underwent significant atmospheric loss by the end of its accretion. Because planetary embryos are massive enough to accrete primordial hydrogen envelopes and because giant impacts are stochastic and occur concurrently with other early atmospheric evolutionary processes, our results suggest a wide diversity in terrestrial planet volatile budgets.<br />Comment: submitted to MNRAS, 9 pages, 4 figures
- Subjects :
- 010504 meteorology & atmospheric sciences
FOS: Physical sciences
chemistry.chemical_element
01 natural sciences
Astrobiology
Atmosphere
Xenon
0103 physical sciences
Thermal
Astrophysics::Solar and Stellar Astrophysics
010303 astronomy & astrophysics
Physics::Atmospheric and Oceanic Physics
Astrophysics::Galaxy Astrophysics
0105 earth and related environmental sciences
Earth and Planetary Astrophysics (astro-ph.EP)
Physics
Atmospheric escape
Astronomy and Astrophysics
Thermal wind
Accretion (astrophysics)
chemistry
Space and Planetary Science
Physics::Space Physics
Terrestrial planet
Astrophysics::Earth and Planetary Astrophysics
Formation and evolution of the Solar System
Astrophysics - Earth and Planetary Astrophysics
Subjects
Details
- ISSN :
- 13652966 and 00358711
- Volume :
- 501
- Database :
- OpenAIRE
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Accession number :
- edsair.doi.dedup.....dbf6877d50ac42b33364c09e0958ae56