A massive primordial atmosphere on early Mars

Fuente: arXiv
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Hauptverfasser: Joiret, Sarah, Morbidelli, Alessandro, Ribeiro, Rafael de Sousa, Avice, Guillaume, Sossi, Paolo
Format: Preprint
Veröffentlicht: 2025
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author Joiret, Sarah
Morbidelli, Alessandro
Ribeiro, Rafael de Sousa
Avice, Guillaume
Sossi, Paolo
author_facet Joiret, Sarah
Morbidelli, Alessandro
Ribeiro, Rafael de Sousa
Avice, Guillaume
Sossi, Paolo
contents Mars finished forming while the solar nebula was still present, and acquired its primordial atmosphere from this reservoir. The absence of a detectable cometary xenon signature in the present-day Martian atmosphere suggests that the capture of solar nebular gas was significant enough to dilute later cometary contributions. By quantifying the mass of cometary material efficiently retained on Mars, we place a lower bound on the mass of the primordial Martian atmosphere. To test the robustness of our conclusions, we use cometary bombardment data from two independent studies conducted within a solar system evolutionary model consistent with its current structure. Our calculations show that, even under the most conservative scenario, the minimal mass of the primordial martian atmospheres would yield a surface pressure of no less than 2.9 bar. Such a massive nebular envelope is consistent with recent models in which atmospheric capture is strongly enhanced by the presence of heavier species on Mars - due to outgassing or redox buffering with a magma ocean.
format Preprint
id arxiv_https___arxiv_org_abs_2509_10060
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A massive primordial atmosphere on early Mars
Joiret, Sarah
Morbidelli, Alessandro
Ribeiro, Rafael de Sousa
Avice, Guillaume
Sossi, Paolo
Earth and Planetary Astrophysics
Mars finished forming while the solar nebula was still present, and acquired its primordial atmosphere from this reservoir. The absence of a detectable cometary xenon signature in the present-day Martian atmosphere suggests that the capture of solar nebular gas was significant enough to dilute later cometary contributions. By quantifying the mass of cometary material efficiently retained on Mars, we place a lower bound on the mass of the primordial Martian atmosphere. To test the robustness of our conclusions, we use cometary bombardment data from two independent studies conducted within a solar system evolutionary model consistent with its current structure. Our calculations show that, even under the most conservative scenario, the minimal mass of the primordial martian atmospheres would yield a surface pressure of no less than 2.9 bar. Such a massive nebular envelope is consistent with recent models in which atmospheric capture is strongly enhanced by the presence of heavier species on Mars - due to outgassing or redox buffering with a magma ocean.
title A massive primordial atmosphere on early Mars
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2509.10060