Atmospheres & Climate

Characterizing Exoplanetary Atmospheres: New Views on Exoplanet Composition and Chemistry

By Keith Cowing
Status Report
May 9, 2024
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Characterizing Exoplanetary Atmospheres: New Views on Exoplanet Composition and Chemistry
Cumulative XUV irradiation vs. planetary escape velocity for a range of rocky exoplanets (grey squares and colored circles) and solar system planets (blue stars). The cumulative lifetime XUV is thought to be the driving force behind planetary evaporation. Atmospheres can be found where gravity is high and solar irradiation is low. The light blue colored line represents the proposed “cosmic shoreline” which follows a power law, IXUV ∝ vesc4 , following [15]. Rocky planets around M dwarfs can be studied with JWST to assess the validity of this shoreline. Plot adapted from [16]. — astro-ph.EP

I review the major open science questions in exoplanet atmospheres. These are mainly focused in the areas of understanding atmospheric physics, the atmosphere as a window into other realms of planetary physics, and the atmosphere is a window into understanding planet formation.

For gas giant planets, high quality spectra have been delivered from JWST and from the ground, enabling the determination of atmospheric abundances.

For the very common sub-Neptune planets, we are just beginning to obtain and interpret JWST spectra.

For the terrestrial planets, which can be studied only around M stars, the field aims to determine if these planets even have long-lived atmospheres.

Jonathan J. Fortney

Comments: To appear in the proceedings of the Pontifical Academy of Science workshop on The James Webb Space Telescope: from first light to new worldviews, Vatican City, 27-29 February 2024
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2405.04587 [astro-ph.EP] (or arXiv:2405.04587v1 [astro-ph.EP] for this version)
Submission history
From: Jonathan J. Fortney
[v1] Tue, 7 May 2024 18:06:02 UTC (398 KB)
Astrobiology, Astrochemistry

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻