Characterizing the Radiative-Convective Structure of Dense Rocky Planet Atmospheres
We use a one-dimensional line-by-line radiative-convective model to simulate hot, dense terrestrial-planet atmospheres.
We find that strong shortwave absorption by H2O and CO2 inhibits near-surface convection, reducing surface temperatures by up to approximately 2000 K compared to fully convective predictions.
Pure CO2 atmospheres are typically 1000 K cooler than pure H2O atmospheres, with only a few percent of H2O needed to elevate surface temperatures by hundreds of kelvin for a fixed incident stellar radiation. We also show that minor greenhouse gases such as SO2 and NH3 have a limited warming effect when H2O is abundant.
Even at insolation values as high as 12,500 W/m2 (about 37 times Earth’s current solar flux), planets with mixed CO2-H2O envelopes have surface temperatures in the 1200 to 2000 K range, limiting surface melting.
Our results highlight the critical role of shortwave heating on magma ocean planets and the need for improved high-temperature spectroscopy beyond 20,000 cm-1.
Jessica Cmiel, Robin Wordsworth, Jacob T. Seeley
Comments: 19 pages, 13 figures. Accepted for publication in The Planetary Science Journal (PSJ). PCM-HiPT source code available at this https URL
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2505.00775 [astro-ph.EP] (or arXiv:2505.00775v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2505.00775
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Submission history
From: Jessica Cmiel
[v1] Thu, 1 May 2025 18:11:53 UTC (4,442 KB)
https://arxiv.org/abs/2505.00775
Astrobiology, Astrochemistry,
