Nightside Clouds on Tidally-locked Terrestrial Planets Mimic Atmosphere-Free Scenarios

Fuente: arXiv
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Main Authors: Powell, Diana, Wordsworth, Robin, Öberg, Karin
Format: Preprint
Published: 2024
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author Powell, Diana
Wordsworth, Robin
Öberg, Karin
author_facet Powell, Diana
Wordsworth, Robin
Öberg, Karin
contents We investigate the impact of nightside cloud formation on the observable night-day contrast of tidally-locked terrestrial planet atmospheres. We demonstrate that, in the case where the planetary dayside is only 10s of Kelvin hotter than the planetary nightside, the presence of optically thick nightside clouds can lead to observations that mimic a planet without an atmosphere, despite the planet actually hosting a significant (10 bar) atmosphere. The scenario presented in this work requires a level of intrinsic atmospheric day/night temperature contrast such that the nightside can form clouds while the dayside is too hot for cloud formation to occur. This scenario is most likely for hotter terrestrials and terrestrials with low volatile inventories. We thus note that a substantial dayside/nightside temperature difference alone does not robustly indicate that a planet does not host an atmosphere and additional observations and modeling are essential for characterization. We further discuss several avenues for future study to improve our understanding of the terrestrial planets and how best to characterize them with JWST.
format Preprint
id arxiv_https___arxiv_org_abs_2409_07542
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Nightside Clouds on Tidally-locked Terrestrial Planets Mimic Atmosphere-Free Scenarios
Powell, Diana
Wordsworth, Robin
Öberg, Karin
Earth and Planetary Astrophysics
We investigate the impact of nightside cloud formation on the observable night-day contrast of tidally-locked terrestrial planet atmospheres. We demonstrate that, in the case where the planetary dayside is only 10s of Kelvin hotter than the planetary nightside, the presence of optically thick nightside clouds can lead to observations that mimic a planet without an atmosphere, despite the planet actually hosting a significant (10 bar) atmosphere. The scenario presented in this work requires a level of intrinsic atmospheric day/night temperature contrast such that the nightside can form clouds while the dayside is too hot for cloud formation to occur. This scenario is most likely for hotter terrestrials and terrestrials with low volatile inventories. We thus note that a substantial dayside/nightside temperature difference alone does not robustly indicate that a planet does not host an atmosphere and additional observations and modeling are essential for characterization. We further discuss several avenues for future study to improve our understanding of the terrestrial planets and how best to characterize them with JWST.
title Nightside Clouds on Tidally-locked Terrestrial Planets Mimic Atmosphere-Free Scenarios
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2409.07542