INFERENCE OF INHOMOGENEOUS CLOUDS IN AN EXOPLANET ATMOSPHERE
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Author(s)
Demory, Brice-Olivier
de Wit, Julien
Lewis, Nikole
Fortney, Jonathan J.
Zsom, Andras
Seager, Sara
Knutson, Heather A.
Heng, Kevin
Madhusudhan, Nikku
Gillon, M.
Date Issued
October 2013
Journal
The Astrophysical Journal
Publisher
IOP Publishing
Citation
Demory, Brice-Olivier, Julien de Wit, Nikole Lewis, Jonathan Fortney, Andras Zsom, Sara Seager, Heather Knutson, et al. “INFERENCE OF INHOMOGENEOUS CLOUDS IN AN EXOPLANET ATMOSPHERE.” The Astrophysical Journal 776, no. 2 (October 20, 2013): L25.
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Author's final manuscript
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.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.1088/2041-8205/776/2/l25
