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| Titel |
Geophysical Limitations on the Habitable Zone: Volcanism and Plate Tectonics |
| VerfasserIn |
Lena Noack, Attilio Rivoldini, Tim Van Hoolst |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250121518
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| Publikation (Nr.) |
 EGU/EGU2016-277.pdf |
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| Zusammenfassung |
| Planets are typically classified as potentially life-bearing planets (i.e. habitable planets) if
they are rocky planets and if a liquid (e.g. water) could exist at the surface. The latter depends
on several factors, like for example the amount of available solar energy, greenhouse effects
in the atmosphere and an efficient CO2-cycle.
However, the definition of the habitable zone should be updated to include possible
geophysical constraints, that could potentially influence the CO2-cycle. Planets like Mars
without plate tectonics and no or only limited volcanic events can only be considered to be
habitable at the inner boundary of the habitable zone, since the greenhouse effect needed
to ensure liquid surface water farther away from the sun is strongly reduced. We
investigate if the planet mass as well as the interior structure can set constraints on the
occurrence of plate tectonics and outgassing, and therefore affect the habitable zone,
using both parameterized evolution models [1] and mantle convection simulations
[1,2].
We find that plate tectonics, if it occurs, always leads to sufficient volcanic outgassing and
therefore greenhouse effect needed for the outer boundary of the habitable zone (several tens
of bar CO2), see also [3]. One-plate planets, however, may suffer strong volcanic
limitations.
The existence of a dense-enough CO2 atmosphere allowing for the carbon-silicate cycle
and release of carbon at the outer boundary of the habitable zone may be strongly limited for
planets: 1) without plate tectonics, 2) with a large planet mass, and/or 3) a high iron
content.
Acknowledgements
This work has been funded by the Interuniversity Attraction Poles Programme initiated by the
Belgian Science Policy Office through the Planet Topers alliance, and results within the
collaboration of the COST Action TD 1308.
References
Noack, L., Rivoldini, A., and Van Hoolst, T.: CHIC –
Coupling Habitability, Interior and Crust, INFOCOMP 2015, ISSN 2308-3484,
ISBN 978-1-61208-416-9, pp. 84-90, IARIA, 2015.
Hüttig, C. and Stemmer, K.: Finite volume discretization for dynamic viscosities
on Voronoi grids, PEPI, Vol 171, pp. 137-146, 2008.
Noack, L. et al.: Constraints for planetary habitability from interior modeling,
PSS, Vol. 98, pp. 14-29, 2014. |
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