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| Titel |
Possible Habitability of Ocean Worlds |
| VerfasserIn |
Lena Noack, Dennis Höning, Jan H. Bredehöft, Helmut Lammer |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250098991
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| Publikation (Nr.) |
 EGU/EGU2014-14725.pdf |
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| Zusammenfassung |
| In the last decade, the number of detected exoplanets has increased to over thousand
confirmed planets and more as yet unconfirmed planet candidates. The scientific community
mainly concentrates on terrestrial planets (up to 10 Earth masses) in the habitable zone,
which describes the distance from the host star where liquid water can exist at the surface
(Kasting et al., 1993).
Another target group of interest are ocean worlds, where a terrestrial-like body (i.e. with an
iron core and a silicate mantle) is covered by a thick water-ice layer - similar to the
icy moons of our solar system but with several Earth masses (e.g. Grasset et al.,
2009).
When an exoplanet is detected and confirmed as a planet, typically the radius and the mass of
it are known, leading to the mean density of the planet that gives hints to possible interior
structures. A planet with a large relative iron core and a thick ocean on top of the silicate
mantle for example would have the same average planet density as a planet with a
more Earth-like appearance (where the main contributor to the mass is the silicate
mantle).
In this study we investigate
how the radius and mass of a planet depend on the amount of water, silicates and
iron present (after Wagner et al., 2011)
the occurence of high-pressure-ice in the water-ice layer (note: we only consider
surface temperatures at which liquid water exists at the surface)
if the ocean layer influences the initiation of plate tectonics
We assume that ocean worlds with a liquid ocean layer (and without the occurence of
high-pressure ice anywhere in the water layer) and plate tectonics (especially the occurence
of subduction zones, hydrothermal vents and continental formation) may be called habitable
(Class III/IV habitats after Lammer et al., 2009).
References:
Kasting, J.F., Whitmire, D.P., and Reynolds, R.T. (1993). Habitable Zones
around Main Sequence Stars. Icarus 101, 108-128.
Grasset, O., Schneider, J., and Sotin, C. (2009). A study of the accuracy of
mass-radius relationships for silicate-rich and ice-rich planets up to 100 Earth
masses. The Astrophysical Journal 693, 722-733.
Wagner, F.W., Sohl, F., Hussmann, H., Grott, M., and Rauer, H. (2011). Interior
structure models of solid exoplanets using material laws in the infinite pressure
limit. Icarus 214, 366-376.
Lammer, H., Bredehöft, J.H., Coustenis, A., Khodachenko, M.L., Kaltenegger,
L., Grasset, O., Prieur, D., Raulin, F., Ehrenfreund, P., Yamauchi, M., Wahlund,
J.-E., Grießmeier, J.-M., Stangl, G., Cockell, C.S., Kulikov, Yu.N., Grenfell, J.L.,
and Rauer, H. (2009). What makes a planet habitable? Astron Astrophys Rev 17,
181-249. |
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