From Global Climate Models (GCMs) to Exoplanet Spectra with the Global Emission Spectra (GlobES)

In the quest to understand the climates and atmospheres of exoplanets, 3D global climate models (GCMs) have become indispensable.

The ability of GCMs to predict atmospheric conditions complements exoplanet observations, creating a feedback loop that enhances our understanding of exoplanetary atmospheres and their environments.

This paper discusses the capabilities of the Global Exoplanet Spectra (GlobES) module of the Planetary Spectrum Generator (PSG), which incorporates 3D atmospheric and surface information into spectral simulations, offering a free, accessible tool for the scientific community to study realistic planetary atmospheres.

Through detailed case studies, including simulations of TRAPPIST1 b, TRAPPIST-1 e, and Earth around Sun, this paper demonstrates the use of GlobES and its effectiveness in simulating transit, emission and reflected spectra, thus supporting the ongoing development and refinement of observational strategies using the James Webb Space Telescope (JWST) and future mission concept studies (e.g., Habitable Worlds Observatory [HWO]) in exoplanet research.

Ray-tracing through a planetary atmosphere involves layer-by-layer variations in ray length and angles within a spherical atmosphere (gray curved lines), as refraction ‘bends’ the light (red traces) along its path. Depending on the degree of bending, the observer may detect radiation originating from the surface, the TOA, or a background star (e.g., during transit observations). — astro-ph.EP

Thomas J. Fauchez, Geronimo L. Villanueva, Vincent Kofman, Gabriella Suissa, Ravi K. Kopparapu

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2507.09048 [astro-ph.EP] (or arXiv:2507.09048v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2507.09048
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Journal reference: Published in Astronomy and Computing Volume 53, October 2025, 100982
Related DOI:
https://doi.org/10.1016/j.ascom.2025.100982
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Submission history
From: Thomas Fauchez
[v1] Fri, 11 Jul 2025 21:45:16 UTC (6,355 KB)
https://arxiv.org/abs/2507.09048
Astrobiology,