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| Titel |
Using polarimetry to retrieve the cloud coverage of Earth-like exoplanets |
| VerfasserIn |
Loic Rossi, Daphne Stam |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250144286
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| Publikation (Nr.) |
 EGU/EGU2017-8095.pdf |
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| Zusammenfassung |
| Clouds in atmospheres of exoplanets play a key role in understanding their climate and
radiative balance. They can also complicate the detection of chemical species in the
atmosphere by flattening the spectra or by creating degeneracies between observables
(Kitzmann et al. 2011, Line and Parmentier 2016)
Polarimetry promises to be a powerfull tool to detect and study exoplanets (Stam et al.
2004). The polarisation of the light scattered by the atmosphere of those planets contains a lot
of information about the vertical structure of the atmosphere and about the composition of the
clouds (Karalidi et al. 2012) and has already been very successful in the case of Venus (Rossi
et al. 2015, 2016 in prep).
We used radiative transfer models based on the doubling-adding method to simulate the
disk-integrated flux and polarisation of light scattered by exoplanets with patchy, subsolar
and polar water clouds. We show that the degree of polarisation of the light scattered by an
exoplanet can be used to discriminate between the different types of cloud coverage and to
quantify the cloud coverage on the planetary scale. Use of both flux and polarisation
allows for a resolution of some ambiguities between cloud coverage and cloud top
altitudes.
We then propose an observational strategy based on an iterative process using polarisation
phase curves in the wavelength range 300 to 900 nm that could help retrieve both orbital
parameters and cloud coverage with minor ambiguities. |
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