Friday, April 26, 2013

1304.6841 (Simchon Faigler et al.)

BEER analysis of Kepler and CoRoT light curves: I. Discovery of a hot Jupiter with superrotation evidence in Kepler data    [PDF]

Simchon Faigler, Lev Tal-Or, Tsevi Mazeh, Dave W. Latham, Lars A. Buchhave
We present the first case in which the BEER algorithm identified a hot Jupiter in the Kepler light curve, and its reality was confirmed by orbital solutions based on follow-up spectroscopy. The companion KIC 4570949b was identified by the BEER algorithm, which detected the BEaming (sometimes called Doppler boosting) effect together with the Ellipsoidal and Reflection/emission modulations (BEER), at an orbital period of 1.54 days, suggesting a planetary companion orbiting the 13.3 mag F star. Further investigation revealed that this star appeared in the Kepler eclipsing binary catalog with estimated primary and secondary eclipse depths of 5e-3 and 1e-4 respectively. Spectroscopic radial-velocity follow-up observations with TRES and SOPHIE confirmed KIC 4570949b as a transiting 2.0+/-0.26 Mjup hot Jupiter. The mass of a transiting planet can be estimated from either the beaming or the ellipsoidal amplitude. The ellipsoidal-based mass estimate of KIC 4570949b is consistent with the spectroscopically measured mass while the beaming-based estimate is significantly inflated. We explain this apparent discrepancy as evidence for the superrotation phenomenon, which involves eastward displacement of the hottest atmospheric spot of a tidally-locked planet by an equatorial super-rotating jet stream. This phenomenon was previously observed only for HD 189733b in the infrared. We show that a phase shift of 10.2+/-2.0 degrees of the planet reflection/emission modulation, due to superrotation, explains the apparently inflated beaming modulation, resolving the ellipsoidal/beaming amplitude discrepancy. KIC 4570949b is one of very few confirmed planets in the Kepler light curves that show BEER modulations and the first to show superrotation evidence in the Kepler band. Its discovery illustrates for the first time the ability of the BEER algorithm to detect short-period planets and brown dwarfs.
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