Rushby, AJ, Johnson, M, Mills, BJW orcid.org/0000-0002-9141-0931 et al. (2 more authors) (2018) Long Term Planetary Habitability and the Carbonate-Silicate Cycle. Astrobiology, 18 (5). pp. 469-480. ISSN 1531-1074
Abstract
The potential habitability of an exoplanet is traditionally assessed by determining whether its orbit falls within the circumstellar “habitable zone” of its star, defined as the distance at which water could be liquid on the surface of a planet (Kopparapu et al.,2013). Traditionally, these limits are determined by radiative-convective climate models, which are used to predict surface temperatures at user-specified levels of greenhouse gases. This approach ignores the vital question of the (bio)geochemical plausibility of the proposed chemical abundances. Carbon dioxide is the most important greenhouse gas in Earth's atmosphere in terms of regulating planetary temperature, with the long-term concentration controlled by the balance between volcanic outgassing and the sequestration of CO2 via chemical weathering and sedimentation, as modulated by ocean chemistry, circulation, and biological (microbial) productivity. We developed a model that incorporates key aspects of Earth's short- and long-term biogeochemical carbon cycle to explore the potential changes in the CO2 greenhouse due to variance in planet size and stellar insolation. We find that proposed changes in global topography, tectonics, and the hydrological cycle on larger planets result in proportionally greater surface temperatures for a given incident flux. For planets between 0.5 and 2 R⊕, the effect of these changes results in average global surface temperature deviations of up to 20 K, which suggests that these relationships must be considered in future studies of planetary habitability.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2018, Mary Ann Liebert, Inc. Final publication is available from Mary Ann Liebert, Inc., publishers https://doi.org/10.1089/ast.2017.1693. |
Keywords: | Planets—Atmospheres—Carbon dioxide—Biogeochemistry |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Earth Surface Science Institute (ESSI) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 09 Jan 2018 16:06 |
Last Modified: | 01 May 2019 00:38 |
Status: | Published |
Publisher: | Mary Ann Liebert |
Identification Number: | 10.1089/ast.2017.1693 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:125975 |