A Hybrid Origin for the Martian Atmosphere
The Martian isotopic record displays a dichotomy in volatile compositions. Interior volatiles from the mantle record a chondritic heritage (e.g., H, N, Kr, Xe) whereas the atmospheric reservoir of Kr and Xe – which do not currently experience escape – record heritage from a solar-like source.
Motivated by disparate inferences on the source of Martian atmospheric volatiles (outgassed versus nebular captured), we consider hybrid-source accretionary atmospheres in which a high molecular weight (e.g., CO2-rich) outgassed component is mixed in with the low molecular weight H2/He-rich nebular atmosphere.
We conduct calculations of nebular capture with and without a mixed-in high molecular weight outgassed component during the lifetime of the solar nebula.
Mixing in an outgassed component enhances the captured nebular inventory by 1-3 orders of magnitude – depending on the outgassed inventory – relative to “pure” nebular capture. These observations and calculations suggest that the Martian atmosphere arose as a hybrid mixture of outgassed and nebular-derived components and that – irrespective of the precise composition of the outgassed component – was mainly composed of molecular hydrogen.
The consequences for Martian atmospheric history are discussed.
Kaveh Pahlevan, Laura Schaefer, Don Porcelli
Comments: 23 Pages, 4 Figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2410.15508 [astro-ph.EP] (or arXiv:2410.15508v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2410.15508
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Submission history
From: Kaveh Pahlevan
[v1] Sun, 20 Oct 2024 20:57:04 UTC (2,784 KB)
https://arxiv.org/abs/2410.15508
Astrobiology,
