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Inference of Inhomogeneous Clouds in an Exoplanet Atmosphere

Demory, Brice-Olivier and de Wit, Julien and Lewis, Nikole and Fortney, Jonathan and Zsom, Andras and Seager, Sara and Knutson, Heather and Heng, Kevin and Madhusudhan, Nikku and Gillon, Michael and Barclay, Thomas and Desert, Jean-Michel and Parmentier, Vivien and Cowan, Nicolas B. (2013) Inference of Inhomogeneous Clouds in an Exoplanet Atmosphere. Astrophysical Journal Letters, 776 (2). Arti No. L25. ISSN 2041-8205. http://resolver.caltech.edu/CaltechAUTHORS:20131104-113210999

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Abstract

We present new visible and infrared observations of the hot Jupiter Kepler-7b to determine its atmospheric properties. Our analysis allows us to (1) refine Kepler-7b's relatively large geometric albedo of Ag = 0.35 ± 0.02, (2) place upper limits on Kepler-7b thermal emission that remains undetected in both Spitzer bandpasses and (3) report a westward shift in the Kepler optical phase curve. We argue that Kepler-7b's visible flux cannot be due to thermal emission or Rayleigh scattering from H2 molecules. We therefore conclude that high altitude, optically reflective clouds located west from the substellar point are present in its atmosphere. We find that a silicate-based cloud composition is a possible candidate. Kepler-7b exhibits several properties that may make it particularly amenable to cloud formation in its upper atmosphere. These include a hot deep atmosphere that avoids a cloud cold trap, very low surface gravity to suppress cloud sedimentation, and a planetary equilibrium temperature in a range that allows for silicate clouds to potentially form in the visible atmosphere probed by Kepler. Our analysis does not only present evidence of optically thick clouds on Kepler-7b but also yields the first map of clouds in an exoplanet atmosphere.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://arxiv.org/abs/1309.7894arXivDiscussion Paper
http://iopscience.iop.org/2041-8205/776/2/L25/PublisherArticle
http://dx.doi.org/10.1088/2041-8205/776/2/L25DOIArticle
ORCID:
AuthorORCID
Demory, Brice-Olivier0000-0002-9355-5165
de Wit, Julien0000-0003-2415-2191
Lewis, Nikole0000-0002-8507-1304
Fortney, Jonathan0000-0002-9843-4354
Knutson, Heather0000-0002-0822-3095
Heng, Kevin0000-0003-1907-5910
Barclay, Thomas0000-0001-7139-2724
Cowan, Nicolas B.0000-0001-6129-5699
Additional Information:© 2013 American Astronomical Society. Received 2013 June 25; accepted 2013 August 20; published 2013 October 3. We thank G. Basri and both anonymous referees for helpful comments that improved the Letter. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the JPL, Caltech under a contract with NASA. A. Zsom was supported by the German Science Foundation (DFG) under grant ZS107/2-1. This work was performed in part under contract with the California Institute of Technology funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. J. de Wit acknowledges support from the Belgian American Educational Foundation and Wallonie-Bruxelles International. Facilities: Kepler, Spitzer
Funders:
Funding AgencyGrant Number
NASA/JPL/CaltechUNSPECIFIED
Deutsche Forschungsgemeinschaft (DFG)ZS107/2-1
NASA Sagan FellowshipUNSPECIFIED
Belgian American Educational FoundationUNSPECIFIED
Wallonie-Bruxelles InternationalUNSPECIFIED
Subject Keywords:planetary systems; stars: individual (Kepler-7); techniques: photometric
Record Number:CaltechAUTHORS:20131104-113210999
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20131104-113210999
Official Citation:Inference of Inhomogeneous Clouds in an Exoplanet Atmosphere Brice-Olivier Demory et al. 2013 ApJ 776 L25
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42222
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:04 Nov 2013 21:08
Last Modified:01 Dec 2017 04:41

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