The Atmospheres of the Hot-Jupiters Kepler-5b and Kepler-6b Observed during Occultations with Warm-Spitzer and Kepler
This paper reports the detection and the measurements of occultations of the two transiting hot giant exoplanets Kepler-5b and Kepler-6b by their parent stars. The observations are obtained in the near-infrared with Warm-Spitzer Space Telescope and at optical wavelengths by combining more than a year of Kepler photometry. The investigation consists of constraining the eccentricities of these systems and of obtaining broadband emergent photometric data for individual planets. For both targets, the occultations are detected at the 3σ level at each wavelength with mid-occultation times consistent with circular orbits. The brightness temperatures of these planets are deduced from the infrared observations and reach T_(Spitzer) = 1930 ± 100 K and T_(Spitzer) = 1660 ± 120 K for Kepler-5b and Kepler-6b, respectively. We measure optical geometric albedos A_g in the Kepler bandpass and find A_g = 0.12 ± 0.04 for Kepler-5b and A_g = 0.11 ± 0.04 for Kepler-6b, leading to upper an limit for the Bond albedo of A_B ≤ 0.17 in both cases. The observations for both planets are best described by models for which most of the incident energy is redistributed on the dayside, with only less than 10% of the absorbed stellar flux redistributed to the nightside of these planets.
Additional Information© 2011 American Astronomical Society. Received 2011 February 3; accepted 2011 October 8; published 2011 November 1. We would like to thank Jessie Christiansen, Brice-Olivier Demory, and Pavel Machaleck for discussions about Kepler photometry, light curves analysis, and interpretation. Thank you to the Spitzer staff at IPAC and in particular to Nancy Silbermann for scheduling the observations of this large program. We would like to thank Jacob Bean for a variety of useful discussions. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. This work is also based on observations made with Kepler which was competitively selected as the tenth Discovery mission. Funding for this mission is provided by NASA's Science Mission Directorate. The authors would like to thank the many people who generously gave so much their time to make this Mission a success. 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 Observatory was made possible by the generous financial support of the W. M. Keck Foundation.
Published - 0067-0049_197_1_11.pdf
Submitted - 1102.0555.pdf