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Carbonate-silicate cycle predictions of Earth-like planetary climates and testing the habitable zone concept
In the conventional habitable zone (HZ) concept, a CO(2)-H(2)O greenhouse maintains surface liquid water. Through the water-mediated carbonate-silicate weathering cycle, atmospheric CO(2) partial pressure (pCO(2)) responds to changes in surface temperature, stabilizing the climate over geologic time...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7708846/ https://www.ncbi.nlm.nih.gov/pubmed/33262334 http://dx.doi.org/10.1038/s41467-020-19896-2 |
Sumario: | In the conventional habitable zone (HZ) concept, a CO(2)-H(2)O greenhouse maintains surface liquid water. Through the water-mediated carbonate-silicate weathering cycle, atmospheric CO(2) partial pressure (pCO(2)) responds to changes in surface temperature, stabilizing the climate over geologic timescales. We show that this weathering feedback ought to produce a log-linear relationship between pCO(2) and incident flux on Earth-like planets in the HZ. However, this trend has scatter because geophysical and physicochemical parameters can vary, such as land area for weathering and CO(2) outgassing fluxes. Using a coupled climate and carbonate-silicate weathering model, we quantify the likely scatter in pCO(2) with orbital distance throughout the HZ. From this dispersion, we predict a two-dimensional relationship between incident flux and pCO(2) in the HZ and show that it could be detected from at least 83 (2σ) Earth-like exoplanet observations. If fewer Earth-like exoplanets are observed, testing the HZ hypothesis from this relationship could be difficult. |
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