A massive exoplanet candidate around KOI-13: Independent confirmation by ellipsoidal variations

Dimitrios Mislis, S. Hodgkin

Research output: Contribution to journalArticle

31 Citations (Scopus)


We present an analysis of the KOI-13.01 candidate exoplanet system included in the 2011 September Kepler data release. The host star is a known and relatively bright (m KP= 9.95) visual binary with a separation significantly smaller (0.8arcsec) than the size of a Kepler pixel (4arcsec pixel -1). The Kepler light curve shows both primary and secondary eclipses, as well as significant out-of-eclipse light-curve variations. We confirm that the transit occurs round the brighter of the two stars. We model the relative contributions from (i) thermal emission from the companion, (ii) planetary reflected light, (iii) Doppler beaming and (iv) ellipsoidal variations in the host star arising from the tidal distortion of the host star by its companion. Our analysis, based on the light curve alone, enables us to constrain the mass of the KOI-13.01 companion to be M C= 8.3 ± 1.25M J and thus demonstrates that the transiting companion is a planet (rather than a brown dwarf which was recently proposed by Szabo). The high temperature of the host star (spectral type A5-7V, T eff= 8511-8020K), combined with the proximity of its companion KOI-13.01, may make it one of the hottest exoplanets known, with a detectable thermal contribution to the light curve even in the Kepler optical passband. However, the single passband of the Kepler light curve does not enable us to unambiguously distinguish between the thermal and reflected components of the planetary emission. Infrared observations may help to break the degeneracy, while radial-velocity follow-up with σ∼ 100 m s -1 precision should confirm the mass of the planet.

Original languageEnglish
Pages (from-to)1512-1517
Number of pages6
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
Publication statusPublished - May 2012
Externally publishedYes



  • Planets and satellites: Detection
  • Planets and satellites: Fundamental parameters
  • Techniques: Photometric

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

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