Chemical evolution of an evaporating lava pool
File(s)
Published version
Author(s)
Curry, Alfred
Mohanty, Subhanjoy
Owen, James E
Type
Journal Article
Abstract
Many known rocky exoplanets are so highly irradiated that their dayside surfaces are molten, and ‘silicate atmospheres’, composed of rock-forming elements, are generated above these lava pools. The compositions of these ‘lava planet’ atmospheres are of great interest because they must be linked to the composition of the underlying rocky interiors. It may be possible to investigate these atmospheres, either by detecting them directly via emission spectroscopy or by observing the dust tails which trail the low mass ‘catastrophically evaporating planets’. In this work, we develop a simple chemical model of the lava pool–atmosphere system under mass loss, to study its evolution. Mass loss can occur both into space and from the day to the nightside. We show that the system reaches a steady state, where the material in the escaping atmosphere has the same composition as that melted into the lava pool from the mantle. We show that the catastrophically evaporating planets are likely to be in this evolved state. This means that the composition of their dust tails is likely to be a direct trace of the composition of the mantle material that is melted into the lava pool. We further show that, due to the strength of day-to-nightside atmospheric transport, this evolved state may even apply to relatively high-mass planets (≳ 1M⊕). Moreover, the low pressure of evolved atmospheres implies that non-detections may not be due to the total lack of an atmosphere. Both conclusions are important for the interpretation of future observations.
Date Issued
2025-01
Date Acceptance
2024-11-01
Citation
Monthly Notices of the Royal Astronomical Society, 2025, 536 (1), pp.913-30
ISSN
0035-8711
Publisher
Oxford University Press
Start Page
913
End Page
30
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
536
Issue
1
Copyright Statement
© The Author(s) 2024. Published by Oxford University Press on behalf of Royal Astronomical Society.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
License URL
Identifier
http://dx.doi.org/10.1093/mnras/stae2583
Publication Status
Published
Article Number
stae2583
Date Publish Online
2024-11-18