The Ice Cap Zone: A Unique Habitable Zone for Ocean Worlds

Traditional definitions of the habitable zone assume that habitable planets contain a carbonate-silicate cycle that regulates CO2 between the atmosphere, surface, and the interior. Such theories have been used to cast doubt on the habitability of ocean worlds. However, Levi et al (2017) have recentl...

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Main Authors: Ramirez, Ramses M., Levi, Amit
Format: Text
Language:unknown
Published: arXiv 2018
Subjects:
Online Access:https://dx.doi.org/10.48550/arxiv.1803.07717
https://arxiv.org/abs/1803.07717
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spelling ftdatacite:10.48550/arxiv.1803.07717 2023-05-15T16:38:21+02:00 The Ice Cap Zone: A Unique Habitable Zone for Ocean Worlds Ramirez, Ramses M. Levi, Amit 2018 https://dx.doi.org/10.48550/arxiv.1803.07717 https://arxiv.org/abs/1803.07717 unknown arXiv https://dx.doi.org/10.1093/mnras/sty761 arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ Earth and Planetary Astrophysics astro-ph.EP FOS Physical sciences article-journal Article ScholarlyArticle Text 2018 ftdatacite https://doi.org/10.48550/arxiv.1803.07717 https://doi.org/10.1093/mnras/sty761 2022-04-01T09:53:13Z Traditional definitions of the habitable zone assume that habitable planets contain a carbonate-silicate cycle that regulates CO2 between the atmosphere, surface, and the interior. Such theories have been used to cast doubt on the habitability of ocean worlds. However, Levi et al (2017) have recently proposed a mechanism by which CO2 is mobilized between the atmosphere and the interior of an ocean world. At high enough CO2 pressures, sea ice can become enriched in CO2 clathrates and sink after a threshold density is achieved. The presence of subpolar sea ice is of great importance for habitability in ocean worlds. It may moderate the climate and is fundamental in current theories of life formation in diluted environments. Here, we model the Levi et al. mechanism and use latitudinally-dependent non-grey energy balance and single-column radiative-convective climate models and find that this mechanism may be sustained on ocean worlds that rotate at least 3 times faster than the Earth. We calculate the circumstellar region in which this cycle may operate for G-M-stars (Teff = 2,600 to 5,800 K), extending from about 1.23 to 1.65, 0.69 to 0.954, 0.38 to 0.528 AU, 0.219 to 0.308 AU, 0.146 to 0.206 AU, and 0.0428 to 0.0617 AU for G2, K2, M0, M3, M5, and M8 stars, respectively. However, unless planets are very young and not tidally locked, our mechanism would be unlikely to apply to stars cooler than a ~M3. We predict C/O ratios for our atmospheres (about 0.5) that can be verified by the JWST mission. : Published in the Monthly Notices of the Royal Astronomical Society (31 pages, 7 Figures, 1 Table) https://doi.org/10.1093/mnras/sty761 Text Ice cap Sea ice DataCite Metadata Store (German National Library of Science and Technology)
institution Open Polar
collection DataCite Metadata Store (German National Library of Science and Technology)
op_collection_id ftdatacite
language unknown
topic Earth and Planetary Astrophysics astro-ph.EP
FOS Physical sciences
spellingShingle Earth and Planetary Astrophysics astro-ph.EP
FOS Physical sciences
Ramirez, Ramses M.
Levi, Amit
The Ice Cap Zone: A Unique Habitable Zone for Ocean Worlds
topic_facet Earth and Planetary Astrophysics astro-ph.EP
FOS Physical sciences
description Traditional definitions of the habitable zone assume that habitable planets contain a carbonate-silicate cycle that regulates CO2 between the atmosphere, surface, and the interior. Such theories have been used to cast doubt on the habitability of ocean worlds. However, Levi et al (2017) have recently proposed a mechanism by which CO2 is mobilized between the atmosphere and the interior of an ocean world. At high enough CO2 pressures, sea ice can become enriched in CO2 clathrates and sink after a threshold density is achieved. The presence of subpolar sea ice is of great importance for habitability in ocean worlds. It may moderate the climate and is fundamental in current theories of life formation in diluted environments. Here, we model the Levi et al. mechanism and use latitudinally-dependent non-grey energy balance and single-column radiative-convective climate models and find that this mechanism may be sustained on ocean worlds that rotate at least 3 times faster than the Earth. We calculate the circumstellar region in which this cycle may operate for G-M-stars (Teff = 2,600 to 5,800 K), extending from about 1.23 to 1.65, 0.69 to 0.954, 0.38 to 0.528 AU, 0.219 to 0.308 AU, 0.146 to 0.206 AU, and 0.0428 to 0.0617 AU for G2, K2, M0, M3, M5, and M8 stars, respectively. However, unless planets are very young and not tidally locked, our mechanism would be unlikely to apply to stars cooler than a ~M3. We predict C/O ratios for our atmospheres (about 0.5) that can be verified by the JWST mission. : Published in the Monthly Notices of the Royal Astronomical Society (31 pages, 7 Figures, 1 Table) https://doi.org/10.1093/mnras/sty761
format Text
author Ramirez, Ramses M.
Levi, Amit
author_facet Ramirez, Ramses M.
Levi, Amit
author_sort Ramirez, Ramses M.
title The Ice Cap Zone: A Unique Habitable Zone for Ocean Worlds
title_short The Ice Cap Zone: A Unique Habitable Zone for Ocean Worlds
title_full The Ice Cap Zone: A Unique Habitable Zone for Ocean Worlds
title_fullStr The Ice Cap Zone: A Unique Habitable Zone for Ocean Worlds
title_full_unstemmed The Ice Cap Zone: A Unique Habitable Zone for Ocean Worlds
title_sort ice cap zone: a unique habitable zone for ocean worlds
publisher arXiv
publishDate 2018
url https://dx.doi.org/10.48550/arxiv.1803.07717
https://arxiv.org/abs/1803.07717
genre Ice cap
Sea ice
genre_facet Ice cap
Sea ice
op_relation https://dx.doi.org/10.1093/mnras/sty761
op_rights arXiv.org perpetual, non-exclusive license
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
op_doi https://doi.org/10.48550/arxiv.1803.07717
https://doi.org/10.1093/mnras/sty761
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