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Atmospheric Characterization of the Hot Jupiter Kepler-13Ab

Shporer, Avi and O'Rourke, Joseph G. and Knutson, Heather A. and Szabó, Gyula M. and Zhao, Ming and Burrows, Adam and Fortney, Jonathan and Agol, Eric and Cowan, Nicolas B. and Désert, Jean-Michel and Howard, Andrew W. and Isaacson, Howard and Lewis, Nikole K. and Showman, Adam P. and Todorov, Kamen O. (2014) Atmospheric Characterization of the Hot Jupiter Kepler-13Ab. Astrophysical Journal, 788 (1). Art. No. 92. ISSN 0004-637X.

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Kepler-13Ab (= KOI-13.01) is a unique transiting hot Jupiter. It is one of very few known short-period planets orbiting a hot A-type star, making it one of the hottest planets currently known. The availability of Kepler data allows us to measure the planet's occultation (secondary eclipse) and phase curve in the optical, which we combine with occultations observed by warm Spitzer at 4.5 μm and 3.6 μm and a ground-based occultation observation in the K_s band (2.1 μm). We derive a day-side hemisphere temperature of 2750 ± 160 K as the effective temperature of a black body showing the same occultation depths. Comparing the occultation depths with one-dimensional planetary atmosphere models suggests the presence of an atmospheric temperature inversion. Our analysis shows evidence for a relatively high geometric albedo, A_g = 0.33^(+0.04)_(-0.06). While measured with a simplistic method, a high A_g is supported also by the fact that the one-dimensional atmosphere models underestimate the occultation depth in the optical. We use stellar spectra to determine the dilution, in the four wide bands where occultation was measured, due to the visual stellar binary companion 1.''15 ± 0.''05 away. The revised stellar parameters measured using these spectra are combined with other measurements, leading to revised planetary mass and radius estimates of M_p = 4.94-8.09 M_J and R_p = 1.406 ± 0.038 R_J. Finally, we measure a Kepler midoccultation time that is 34.0 ± 6.9 s earlier than expected based on the midtransit time and the delay due to light-travel time and discuss possible scenarios.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper DOIArticle
Shporer, Avi0000-0002-1836-3120
O'Rourke, Joseph G.0000-0002-1180-996X
Knutson, Heather A.0000-0002-0822-3095
Zhao, Ming0000-0002-4258-9517
Burrows, Adam0000-0002-3099-5024
Fortney, Jonathan0000-0002-9843-4354
Agol, Eric0000-0002-0802-9145
Cowan, Nicolas B.0000-0001-6129-5699
Désert, Jean-Michel0000-0002-0875-8401
Howard, Andrew W.0000-0001-8638-0320
Isaacson, Howard0000-0002-0531-1073
Lewis, Nikole K.0000-0002-8507-1304
Todorov, Kamen O.0000-0002-9276-8118
Additional Information:© 2014 The American Astronomical Society. Received 2014 January 29; accepted 2014 April 11; published 2014 May 27. A.S. thanks Ehud Nakar and Jason Eastman for enlightening discussions. This work was performed in part at the Jet Propulsion Laboratory, under contract with the California Institute of Technology (Caltech) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. J.G.O. receives support from the National Science Foundation’s Graduate Research Fellowship Program. Gy.M.Sz. was supported by the Hungarian OTKA grants 104607 and 83790, the HUMAN MB08C 81013 grant of the MAG Zrt, and the János Bolyai Research Fellowship and a Lendület-2009 grant of the Hungarian Academy of Sciences. M.Z. is supported by the Center for Exoplanets and Habitable Worlds (CEHW) at the Pennsylvania State University. The Palomar/WIRC observation was in part supported by NASA through the American Astronomical Society’s Small Research Grant program. This research has made use of NASA’s Astrophysics Data System Service. This work is based on observations made by the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. The Palomar 200 inch (5 m) Hale Telescope (P200) is operated by Caltech, JPL, and Cornell University. Kepler was competitively selected as the tenth NASA Discovery mission. Funding for this mission is provided by the NASA Science Mission Directorate. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Keck Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Facilities: Warm Spitzer, P200/WIRC, Kepler, Keck/ HIRES, P200/PHARO
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
Hungarian Academy of Sciences (OTKA)104607
Hungarian Academy of Sciences (OTKA)83790
MAG Zrt HUMANMB08C 81013
János Bolyai Research FellowshipUNSPECIFIED
Center for Exoplanets and Habitable WorldsUNSPECIFIED
American Astronomical SocietyUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:planetary systems; stars: early-type; stars: individual (Kepler-13 BD+46 2629); techniques: photometric; techniques: spectroscopic
Issue or Number:1
Record Number:CaltechAUTHORS:20140708-112006314
Persistent URL:
Official Citation:Atmospheric Characterization of the Hot Jupiter Kepler-13Ab Avi Shporer et al. 2014 ApJ 788 92
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:47076
Deposited By: Tony Diaz
Deposited On:08 Jul 2014 19:33
Last Modified:09 Mar 2020 13:18

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