Exoplanets & Exomoons

Transiting Exoplanet Atmospheres In The Era of JWST

By Keith Cowing
Status Report
April 25, 2024
Filed under , , , , ,
Transiting Exoplanet Atmospheres In The Era of JWST
Distribution of confirmed exoplanets in mass-period space. Planets with spectroscopic measurements that constrain their atmospheric properties are shown as dark points, those without are shown as light points. This review article focuses on atmospheric characterization of transiting exoplanets, i.e. the dark purple pentagon symbols. Solar system planets are shown as yellow circles for context. Both the radial velocity and transit techniques are most sensitive to detecting massive planets on close-in orbits, while the direct imaging technique is most sensitive to young, self-luminous planets on relatively wide orbits. Figure adapted from Currie et al. (2023). — astro-ph.EP

The field of exoplanet atmospheric characterization has recently made considerable advances with the advent of high-resolution spectroscopy from large ground-based telescopes and the commissioning of the James Webb Space Telescope (JWST).

We have entered an era in which atmospheric compositions, aerosol properties, thermal structures, mass loss, and three-dimensional effects can be reliably constrained. While the challenges of remote sensing techniques imply that individual exoplanet atmospheres will likely never be characterized to the degree of detail that is possible for solar system bodies, exoplanets present an exciting opportunity to characterize a diverse array of worlds with properties that are not represented in our solar system.

This review article summarizes the current state of exoplanet atmospheric studies for transiting planets. We focus on how observational results inform our understanding of exoplanet properties and ultimately address broad questions about planetary formation, evolution, and diversity. This review is meant to provide an overview of the exoplanet atmospheres field for planetary- and geo-scientists without astronomy backgrounds, and exoplanet specialists, alike.

We give special attention to the first year of JWST data and recent results in high-resolution spectroscopy that have not been summarized by previous review articles.

Measured masses and radii for small planets orbiting small (M dwarf) stars from Luque & Pall´e (2022). This sample only includes the subset of planets with small fractional uncertainties in mass and radius. Theoretical mass-radius relations for planets with an Earth-like bulk composition (dashed brown line), half water and half Earth-like (solid blue line), and Earth-like with a few percent hydrogen-rich atmosphere (dashed orange line) are overplotted for comparison. The light orange shading denotes the range of possible hydrogen-rich atmospheres that can be retained by these planets under a range of possible starting assumptions. Figure adapted from Rogers et al. (2023). — astro-ph.EP

Eliza M.-R. Kempton, Heather A. Knutson

Comments: Chapter 12 accepted for publication in the Reviews in Mineralogy and Geochemistry (RiMG) Volume 90 on “Exoplanets: Compositions, Mineralogy, and Evolution” edited by Natalie Hinkel, Keith Putirka, and Siyi Xu; 62 pages, 15 figures, and 5 equations
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR); Geophysics (physics.geo-ph)
Cite as: arXiv:2404.15430 [astro-ph.EP] (or arXiv:2404.15430v1 [astro-ph.EP] for this version)
Submission history
From: Eliza Kempton [via Natalie Hinkel as proxy]
[v1] Tue, 23 Apr 2024 18:19:37 UTC (9,790 KB)


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) 🖖🏻