Exoplanets & Exomoons

The Effect Of Cloudy Atmospheres On The Thermal Evolution Of Warm Giant Planets From An Interior Modelling Perspective

By Keith Cowing
Status Report
astro-ph.EP
March 3, 2024
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The Effect Of Cloudy Atmospheres On The Thermal Evolution Of Warm Giant Planets From An Interior Modelling Perspective
The model setup in this work: A Jovian planet is irradiated by its star. The atmosphere acts as a bottleneck for the incoming irradiation flux and the outgoing intrinsic heat flux, indicated by arrows. The interior consists of a radiative atmosphere, an outer convective envelope, and an isothermal core. The main constituents are hydrogen and helium, replenished by metals. We consider clouds in the atmosphere and combine atmosphere, interior, and thermal evolution models to obtain the radius evolution of the planet. The atmosphere model is used as an outer boundary condition for the interior model, connecting both models at the radiative-convective boundary — astro-ph.EP

We are interested in the influence of cloudy atmospheres on the thermal radius evolution of warm exoplanets from an interior modelling perspective. By applying a physically motivated but simple parameterized cloud model, we obtain the atmospheric P-T structure that is connected to the adiabatic interior at the self-consistently calculated radiative-convective boundary.

We investigate the impact of cloud gradients, with the possibility of inhibiting superadiabatic clouds. Furthermore, we explore the impact on the radius evolution for a cloud base fixed at a certain pressure versus a subsiding cloud base during the planets’ thermal evolution. We find that deep clouds clearly alter the evolution tracks of warm giants, leading to either slower/faster cooling than in the cloudless case (depending on the cloud model used).

When comparing the fixed versus dynamic cloud base during evolution, we see an enhanced behaviour resulting in a faster or slower cooling in the case of the dynamic cloud base. We show that atmospheric models including deep clouds can lead to degeneracy in predicting the bulk metallicity of planets, ZP. For WASP-10b, we find a possible span of ≈ZP+0.10−0.06. For TOI-1268b, it is ≈ZP+0.10−0.05. Further work on cloud properties during the long-term evolution of gas giants is needed to better estimate the influence on the radius evolution.

Anna Julia Poser, Ronald Redmer

Comments: 17 pages, 10 figures, accepted for publication in MNRAS
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2402.19466 [astro-ph.EP] (or arXiv:2402.19466v1 [astro-ph.EP] for this version)
Submission history
From: Anna Julia Poser
[v1] Thu, 29 Feb 2024 18:55:41 UTC (5,223 KB)
https://arxiv.org/abs/2402.19466
Astrobiology,

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) 🖖🏻