The erosion of large primary atmospheres typically leaves behind substantial secondary atmospheres on temperate rocky planets

Fuente: arXiv
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Main Authors: Krissansen-Totton, Joshua, Wogan, Nicholas, Thompson, Maggie, Fortney, Jonathan J.
Format: Preprint
Published: 2024
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_version_ 1866913521305911296
author Krissansen-Totton, Joshua
Wogan, Nicholas
Thompson, Maggie
Fortney, Jonathan J.
author_facet Krissansen-Totton, Joshua
Wogan, Nicholas
Thompson, Maggie
Fortney, Jonathan J.
contents Exoplanet exploration has revealed that many$\unicode{x2013}$perhaps most$\unicode{x2013}$terrestrial exoplanets formed with substantial H$_2$-rich envelopes, seemingly in contrast to solar system terrestrials, for which there is scant evidence of long-lived primary atmospheres. It is not known how a long-lived primary atmosphere might affect the subsequent habitability prospects of terrestrial exoplanets. Here, we present a new, self-consistent evolutionary model of the transition from primary to secondary atmospheres. The model incorporates all Fe-C-O-H-bearing species and simulates magma ocean solidification, radiative-convective climate, thermal escape, and mantle redox evolution. For our illustrative example TRAPPIST-1, our model strongly favors atmosphere retention for the habitable zone planet TRAPPIST-1e. In contrast, the same model predicts a comparatively thin atmosphere for the Venus-analog TRAPPIST-1b, which would be vulnerable to complete erosion via non-thermal escape and is consistent with JWST observations. More broadly, we conclude that the erosion of primary atmospheres typically does not preclude surface habitability, and frequently results in large surface water inventories due to the reduction of FeO by H$_2$.
format Preprint
id arxiv_https___arxiv_org_abs_2409_18940
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The erosion of large primary atmospheres typically leaves behind substantial secondary atmospheres on temperate rocky planets
Krissansen-Totton, Joshua
Wogan, Nicholas
Thompson, Maggie
Fortney, Jonathan J.
Earth and Planetary Astrophysics
Exoplanet exploration has revealed that many$\unicode{x2013}$perhaps most$\unicode{x2013}$terrestrial exoplanets formed with substantial H$_2$-rich envelopes, seemingly in contrast to solar system terrestrials, for which there is scant evidence of long-lived primary atmospheres. It is not known how a long-lived primary atmosphere might affect the subsequent habitability prospects of terrestrial exoplanets. Here, we present a new, self-consistent evolutionary model of the transition from primary to secondary atmospheres. The model incorporates all Fe-C-O-H-bearing species and simulates magma ocean solidification, radiative-convective climate, thermal escape, and mantle redox evolution. For our illustrative example TRAPPIST-1, our model strongly favors atmosphere retention for the habitable zone planet TRAPPIST-1e. In contrast, the same model predicts a comparatively thin atmosphere for the Venus-analog TRAPPIST-1b, which would be vulnerable to complete erosion via non-thermal escape and is consistent with JWST observations. More broadly, we conclude that the erosion of primary atmospheres typically does not preclude surface habitability, and frequently results in large surface water inventories due to the reduction of FeO by H$_2$.
title The erosion of large primary atmospheres typically leaves behind substantial secondary atmospheres on temperate rocky planets
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2409.18940