Reference : The High Albedo of the Hot Jupiter Kepler-7 b
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/95412
The High Albedo of the Hot Jupiter Kepler-7 b
English
Demory, Brice*-Olivier [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA]
Seager, Sara [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA]
Madhusudhan, Nikku [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544, USA]
Kjeldsen, Hans [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark]
Christensen-Dalsgaard, Jørgen [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark]
Gillon, Michaël mailto [Institut d'Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août, 17, Bat. B5C, Liège 1, Belgium]
Rowe, Jason F [NASA Ames Research Center, Moffett Field, CA 94035, USA]
Welsh, William F [Astronomy Department, San Diego State University, San Diego, CA 92182, USA]
Adams, Elisabeth R [Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge, MA 02138, USA]
Dupree, Andrea [Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge, MA 02138, USA]
McCarthy, Don [Steward Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721, USA]
Kulesa, Craig [Steward Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721, USA]
Borucki, William J [NASA Ames Research Center, Moffett Field, CA 94035, USA]
Koch, David G [NASA Ames Research Center, Moffett Field, CA 94035, USA]
1-Jul-2011
Astrophysical Journal
University of Chicago Press
735
L12
Yes (verified by ORBi)
International
0004-637X
1538-4357
Chicago
IL
[en] planetary systems ; stars: individual: Kepler-7 KIC 5780885 2MASS 19141956+4105233 ; techniques: photometric
[en] Hot Jupiters are expected to be dark from both observations (albedo upper limits) and theory (alkali metals and/or TiO and VO absorption). However, only a handful of hot Jupiters have been observed with high enough photometric precision at visible wavelengths to investigate these expectations. The NASA Kepler mission provides a means to widen the sample and to assess the extent to which hot Jupiter albedos are low. We present a global analysis of Kepler-7 b based on Q0-Q4 data, published radial velocities, and asteroseismology constraints. We measure an occultation depth in the Kepler bandpass of 44 ± 5 ppm. If directly related to the albedo, this translates to a Kepler geometric albedo of 0.32 ± 0.03, the most precise value measured so far for an exoplanet. We also characterize the planetary orbital phase light curve with an amplitude of 42 ± 4 ppm. Using atmospheric models, we find it unlikely that the high albedo is due to a dominant thermal component and propose two solutions to explain the observed planetary flux. First, we interpret the Kepler-7 b albedo as resulting from an excess reflection over what can be explained solely by Rayleigh scattering, along with a nominal thermal component. This excess reflection might indicate the presence of a cloud or haze layer in the atmosphere, motivating new modeling and observational efforts. Alternatively, the albedo can be explained by Rayleigh scattering alone if Na and K are depleted in the atmosphere by a factor of 10-100 below solar abundances.
http://hdl.handle.net/2268/95412
10.1088/2041-8205/735/1/L12
http://adsabs.harvard.edu/abs/2011ApJ...735L..12D
http://de.arxiv.org/abs/1105.5143

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