Kepler KOI-13.01 - Detection of beaming and ellipsoidal modulations pointing to a massive hot Jupiter

KOI-13 was presented by the Kepler team as a candidate for having a giant planet — KOI-13.01, with orbital period of 1.7 d and transit depth of∼0.8%. We have analyzed the Kepler Q2 data of KOI-13, which was publicly available at the time of the submission of this paper, and derived the amplitudes of the beaming, ellipsoidal and reflection mo dulations — 8.6± 1.1, 66.8± 1.6 and 72.0± 1.5 ppm (parts per million), respectively. After the paper was submitted, Q3 data were released, so we repeated the analysis with the newly available light curve. The results of the two quarters were quite similar. From the amplitudes of the beaming and the ellipsoidal modulations we derived two independent estimates of the mass of the secondary. Both estimates, 6± 3 MJup and 4± 2 MJup, suggested that KOI-13.01 was a massive planet, with one of the largest known radii. We also found in the data a periodicity of unknown origin with a period of 1.0595 d and a peak-to-peak modulation of∼60 ppm. The light curve of Q3 revealed a few more small-amplitude periodicity with similar frequencies. It seemed as if the secondary occultation of KOI-13 was slightly deeper than the reflection peakto-peak modulation by 16.8± 4.5 ppm. If real, this small difference was a measure of the thermal emission from the night side of KOI-13.01. We estimated the effective temperature to be 2600± 150 K, using a simplistic black-body emissivity approximation. We then derived the planetary geometrical and Bond albedos as a function of the day-side temperature. Our analysis suggested that the Bond albedo of KOI-13.01 might be substantially larger than the geometrical albedo.

[1]  Tsevi Mazeh,et al.  Detection of the ellipsoidal and the relativistic beaming effects in the CoRoT-3 lightcurve , 2010, 1008.3028.

[2]  A. Collier Cameron,et al.  Thermal emission at 4.5 and 8 μm of WASP-17b, an extremely large planet in a slightly eccentric orbit , 2011, 1101.5620.

[3]  D. Fabrycky,et al.  A THIRD HOT WHITE DWARF COMPANION DETECTED BY KEPLER , 2010, 1009.3271.

[4]  F. Allard,et al.  The effect of evaporation on the evolution of close-in giant planets , 2004, astro-ph/0404101.

[5]  K. Kinemuchi,et al.  KEPLER-10 c: A 2.2 EARTH RADIUS TRANSITING PLANET IN A MULTIPLE SYSTEM , 2011, 1105.4647.

[6]  P. Etzel,et al.  Photometric orbits of seven detached eclipsing binaries , 1981 .

[7]  Gilles Chabrier,et al.  Heat transport in giant (exo)planets: a new perspective , 2007 .

[8]  Tsevi Mazeh,et al.  Automated analysis of eclipsing binary light curves – I. EBAS – a new Eclipsing Binary Automated Solver with ebop , 2006, astro-ph/0601199.

[9]  M. R. Haas,et al.  A closely packed system of low-mass, low-density planets transiting Kepler-11 , 2011, Nature.

[10]  S. L. Morris,et al.  The ellipsoidal variable stars. , 1985 .

[11]  C. Moutou,et al.  SOPHIE velocimetry of Kepler transit candidates IV. KOI-196b: a non-inflated hot-Jupiter with a high albedo , 2011, 1108.0550.

[12]  F. Fressin,et al.  CHARACTERISTICS OF PLANETARY CANDIDATES OBSERVED BY KEPLER. II. ANALYSIS OF THE FIRST FOUR MONTHS OF DATA , 2011, 1102.0541.

[13]  Timothy M. Brown,et al.  KEPLER INPUT CATALOG: PHOTOMETRIC CALIBRATION AND STELLAR CLASSIFICATION , 2011, 1102.0342.

[14]  Robert E. Wilson,et al.  Realization of Accurate Close-Binary Light Curves: Application to MR Cygni , 1971 .

[15]  A. Loeb,et al.  Periodic Flux Variability of Stars due to the Reflex Doppler Effect Induced by Planetary Companions , 2003, astro-ph/0303212.

[16]  D. W. Latham,et al.  HAT-P-32b AND HAT-P-33b: TWO HIGHLY INFLATED HOT JUPITERS TRANSITING HIGH-JITTER STARS , 2011, 1106.1212.

[17]  E. Agol,et al.  THE STATISTICS OF ALBEDO AND HEAT RECIRCULATION ON HOT EXOPLANETS , 2009, 1001.0012.

[18]  A. Lagrange,et al.  Planets and brown dwarfs around A–F main-sequence stars: performances of radial-velocity surveys with HARPS and first detections , 2010 .

[19]  H. Lehmann,et al.  ASYMMETRIC TRANSIT CURVES AS INDICATION OF ORBITAL OBLIQUITY: CLUES FROM THE LATE-TYPE DWARF COMPANION IN KOI-13 , 2011, 1105.2524.

[20]  Department of Physics,et al.  HAT-P-7b: An Extremely Hot Massive Planet Transiting a Bright Star in the Kepler Field , 2008, 0803.0746.

[21]  N. Ahmed,et al.  Discrete Cosine Transform , 1996 .

[22]  et al,et al.  Transiting exoplanets from the CoRoT space mission . VI. CoRoT-Exo-3b: the first secure inhabitant of the brown-dwarf desert , 2008, 0810.0919.

[23]  Richard S. Freedman,et al.  A Unified Theory for the Atmospheres of the Hot and Very Hot Jupiters: Two Classes of Irradiated Atmospheres , 2007, 0710.2558.

[24]  T. Mazeh.  Observational Evidence for Tidal Interaction in Close Binary Systems , 2007, 0801.0134.

[25]  Howard Isaacson,et al.  Kepler Planet-Detection Mission: Introduction and First Results , 2010, Science.

[26]  Tel Aviv,et al.  Beaming Binaries: A New Observational Category of Photometric Binary Stars , 2007, 0708.2100.

[27]  R.G.West,et al.  WASP-25b: A 0.6M planet in the Southern hemisphere , 2010, 1009.5917.

[28]  Mark S. Marley,et al.  Planetary Radii across Five Orders of Magnitude in Mass and Stellar Insolation: Application to Transits , 2006 .

[29]  Sara Seager,et al.  THE HIGH ALBEDO OF THE HOT JUPITER KEPLER-7 b , 2011, 1105.5143.

[30]  Howard Isaacson,et al.  MODELING KEPLER TRANSIT LIGHT CURVES AS FALSE POSITIVES: REJECTION OF BLEND SCENARIOS FOR KEPLER-9, AND VALIDATION OF KEPLER-9 d, A SUPER-EARTH-SIZE PLANET IN A MULTIPLE SYSTEM , 2010, 1008.4393.

[31]  J. Fortney,et al.  INFLATING AND DEFLATING HOT JUPITERS: COUPLED TIDAL AND THERMAL EVOLUTION OF KNOWN TRANSITING PLANETS , 2009, 0907.1268.

[32]  S. Albrecht,et al.  The changing phases of extrasolar planet CoRoT-1b , 2009, Nature.

[33]  D. Queloz,et al.  Extrasolar planets and brown dwarfs around A-F type stars. I. Performances of radial velocity measurements, first analyses of variations , 2005 .

[34]  Oxford,et al.  OBSERVATIONS OF DOPPLER BOOSTING IN KEPLER LIGHT CURVES , 2010, 1001.4539.

[35]  T. Mazeh,et al.  Photometric detection of non-transiting short-period low-mass companions through the beaming, ellipsoidal and reflection effects in Kepler and CoRoT light curves , 2011, 1106.2713.

[36]  R. L. Kurucz,et al.  New Grids of ATLAS9 Model Atmospheres , 2004, astro-ph/0405087.

[37]  Michael C. Liu,et al.  RETIRED A STARS AND THEIR COMPANIONS. III. COMPARING THE MASS–PERIOD DISTRIBUTIONS OF PLANETS AROUND A-TYPE STARS AND SUN-LIKE STARS , 2009, 0912.0518.

[38]  Sara Seager,et al.  THE DISCOVERY OF ELLIPSOIDAL VARIATIONS IN THE KEPLER LIGHT CURVE OF HAT-P-7 , 2010, 1001.0413.

[39]  E. Agol,et al.  Analytic Light Curves for Planetary Transit Searches , 2002, astro-ph/0210099.

[40]  Tristan Guillot,et al.  Astronomy and Astrophysics Evolution of " 51 Peg B-like " Planets , 2001 .

[41]  S. L. Morris,et al.  The equations of ellipsoidal star variability applied to HR 8427 , 1993 .

[42]  J. Scargle.  Studies in astronomical time series analysis. II - Statistical aspects of spectral analysis of unevenly spaced data , 1982 .

[43]  S. Faigler,et al.  SEVEN NEW BINARIES DISCOVERED IN THE KEPLER LIGHT CURVES THROUGH THE BEER METHOD CONFIRMED BY RADIAL-VELOCITY OBSERVATIONS , 2011, 1110.2133.