Atmospheres & Climate

The Evaporation Of Planetary Atmospheres

By Keith Cowing
Status Report
November 8, 2023
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The Evaporation Of Planetary Atmospheres
This artist’s illustration shows a giant cloud of hydrogen streaming off a warm, Neptune-sized planet just 97 light-years from Earth. The exoplanet is tiny compared to its star. — NASA

In recent years the focus of exoplanet research has shifted from the mere detection to detailed characterization. Precise measurements of the masses and radii of transiting planets have shown that some low-mass planets have extended atmospheres while others are bare rocks. Hybrid atmospheres consisting of a mixture of Hydrogen and large amount of heavy elements have also been detected.

A key factor in explaining this diversity of planetary atmospheres is the erosion by the X-ray and EUV-radiation (XUV) from the host-star. The evaporation through XUV-radiation has already been measured for a few exoplanets.The apparent weakness of the CaIIHK and the MgIIhk emission cores has been interpreted as evidence for the evaporation of planetary atmospheres.

The interpretation is that the evaporating material from the planet forms a thick torus which absorbs the C,IIHK and the MgIIhk lines from the host star. In this contribution a new way how to prove, or disprove this hypothesis by observations is proposed. It is furthermore shown that there are enough bright targets are already known that can be observed, and more will be found with the PLATO mission.

E.W. Guenther, L. Fossati, P. Kabath

Comments: 8 page with 3 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2311.02965 [astro-ph.EP] (or arXiv:2311.02965v1 [astro-ph.EP] for this version)
Submission history
From: Eike Guenther
[v1] Mon, 6 Nov 2023 09:08:09 UTC (213 KB)

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) 🖖🏻