Liu, B, Marsh, DR, Walsh, C orcid.org/0000-0001-6078-786X et al. (1 more author) (2023) Higher Water Loss on Earth-like Exoplanets in Eccentric Orbits. Monthly Notices of the Royal Astronomical Society. ISSN 0035-8711
Abstract
The climate of a terrestrial exoplanet is controlled by the type of host star, the orbital configuration and the characteristics of the atmosphere and the surface. Many rocky exoplanets have higher eccentricities than those in the Solar System, and about 18% of planets with masses <10 M⊕ have e > 0.1. Underexplored are the implications of such high eccentricities on the atmosphere, climate, and potential habitability on such planets. We use WACCM6, a state-of-the-art fully-coupled Earth-system model, to simulate the climates of two Earth-like planets; one in a circular orbit (e = 0), and one in an eccentric orbit (e = 0.4) with the same mean insolation. We quantify the effects of eccentricity on the atmospheric water abundance and loss given the importance of liquid water for habitability. The asymmetric temperature response in the eccentric orbit results in a water vapour mixing ratio in the stratosphere (>20 ppmv) that is approximately five times greater than that for circular orbit (∼4 ppmv). This leads to at most ∼3 times increases in both the atmospheric hydrogen loss rate and the ocean loss rate compared with the circular case. Using the Planetary Spectrum Generator, we simulate the idealised transmission spectra for both cases. We find that the water absorption features are stronger at all wavelengths for the e = 0.4 spectrum than for the circular case. Hence, highly-eccentric Earth-like exoplanets may be prime targets for future transmission spectroscopy observations to confirm, or otherwise, the presence of atmospheric water vapour.
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Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | This is an author produced version of an article published in in Monthly Notices of the Royal Astronomical Society , made available under the terms of the Creative Commons Attribution License (CC-BY), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | planets and satellites: terrestrial planets, planets and satellites: atmospheres, planets and satellites: physical evolution |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Funding Information: | Funder Grant number STFC (Science and Technology Facilities Council) ST/X001016/1 STFC (Science and Technology Facilities Council) ST/T000287/1 MRC (Medical Research Council) MR/T040726/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 26 Jul 2023 11:58 |
Last Modified: | 26 Jul 2023 16:31 |
Published Version: | http://dx.doi.org/10.1093/mnras/stad1828 |
Status: | Published online |
Publisher: | Oxford University Press |
Identification Number: | 10.1093/mnras/stad1828 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:200835 |
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