Mapping the SO2 Shoreline in Gas Giant Exoplanets

Fuente: arXiv
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Autores principales: Crossfield, Ian J. M., Ahrer, Eva-Maria, Brande, Jonathan, Kreidberg, Laura, Lothringer, Joshua, Piaulet-Ghorayeb, Caroline, Polman, Jesse, Welbanks, Luis, Kirk, James, Powell, Diana, Khorshid, Niloofar
Formato: Preprint
Publicado: 2025
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author Crossfield, Ian J. M.
Ahrer, Eva-Maria
Brande, Jonathan
Kreidberg, Laura
Lothringer, Joshua
Piaulet-Ghorayeb, Caroline
Polman, Jesse
Welbanks, Luis
Kirk, James
Powell, Diana
Khorshid, Niloofar
author_facet Crossfield, Ian J. M.
Ahrer, Eva-Maria
Brande, Jonathan
Kreidberg, Laura
Lothringer, Joshua
Piaulet-Ghorayeb, Caroline
Polman, Jesse
Welbanks, Luis
Kirk, James
Powell, Diana
Khorshid, Niloofar
contents JWST has revealed sulfur chemistry in giant exoplanet atmospheres, where molecules such as SO2 trace photochemistry, metallicity, and formation and migration. To ascertain the conditions that determine whether (or how much) SO2, H2S, and other sulfur-bearing species are present in exoplanet atmospheres, we present a grid of planetary atmospheres covering metallicities from 0.3-1000x Solar and temperatures from 250-2050 K. These models map out the 'SO2 shoreline,' the region of metallicity and irradiation for which SO2 may be sufficiently abundant to be detectable. SO2 is a sensitive indicator of metallicity; expected SO2 abundances also depend strongly on overall temperature and C/O ratio; the SO2 abundance depends surprisingly weakly on XUV irradiation, also weakly on Kzz (for Teq > 600 K), and is essentially independent of internal temperature. Despite its detection in a growing number of giant planets, SO2 is never the dominant sulfur-bearing molecule: depending on temperature and metallicity, H2S, S2, NS, SO, SH, and even S8 or atomic S are frequently as common (or more so) as SO2. Nonetheless SO2 remains the most easily detectable sulfur-bearing species, followed by H2S, though perhaps SO and SH could be detectable in some gas giants. Aside from a pressing need for additional observational constraints on sulfur, we also identify the need for future work to account for the effects of clouds and hazes, fully self-consistent atmospheric models, 2D and 3D models, a wider range of planetary masses and radii, and studies to measure and refine reaction rates and molecular opacities of sulfur-bearing species
format Preprint
id arxiv_https___arxiv_org_abs_2509_14318
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Mapping the SO2 Shoreline in Gas Giant Exoplanets
Crossfield, Ian J. M.
Ahrer, Eva-Maria
Brande, Jonathan
Kreidberg, Laura
Lothringer, Joshua
Piaulet-Ghorayeb, Caroline
Polman, Jesse
Welbanks, Luis
Kirk, James
Powell, Diana
Khorshid, Niloofar
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
JWST has revealed sulfur chemistry in giant exoplanet atmospheres, where molecules such as SO2 trace photochemistry, metallicity, and formation and migration. To ascertain the conditions that determine whether (or how much) SO2, H2S, and other sulfur-bearing species are present in exoplanet atmospheres, we present a grid of planetary atmospheres covering metallicities from 0.3-1000x Solar and temperatures from 250-2050 K. These models map out the 'SO2 shoreline,' the region of metallicity and irradiation for which SO2 may be sufficiently abundant to be detectable. SO2 is a sensitive indicator of metallicity; expected SO2 abundances also depend strongly on overall temperature and C/O ratio; the SO2 abundance depends surprisingly weakly on XUV irradiation, also weakly on Kzz (for Teq > 600 K), and is essentially independent of internal temperature. Despite its detection in a growing number of giant planets, SO2 is never the dominant sulfur-bearing molecule: depending on temperature and metallicity, H2S, S2, NS, SO, SH, and even S8 or atomic S are frequently as common (or more so) as SO2. Nonetheless SO2 remains the most easily detectable sulfur-bearing species, followed by H2S, though perhaps SO and SH could be detectable in some gas giants. Aside from a pressing need for additional observational constraints on sulfur, we also identify the need for future work to account for the effects of clouds and hazes, fully self-consistent atmospheric models, 2D and 3D models, a wider range of planetary masses and radii, and studies to measure and refine reaction rates and molecular opacities of sulfur-bearing species
title Mapping the SO2 Shoreline in Gas Giant Exoplanets
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2509.14318