Spin-Orbit Misalignment and Precession in the Kepler-13Ab Planetary System

Miranda K. Herman, Ernst J.W. De Mooij, Chelsea X. Huang, Ray Jayawardhana

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9 Citations (Scopus)
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Gravity darkening induced by rapid stellar rotation provides us with a unique opportunity to characterize the spin-orbit misalignment of a planetary system through analysis of its photometric transit. We use the gravity-darkened transit modeling code simuTrans to reproduce the transit light curve of Kepler-13Ab by separately analyzing phase-folded transits for 12 short-cadence Kepler quarters. We verify the temporal change in impact parameter indicative of spin-orbit precession identified by Szabó et al. and Masuda, reporting a rate of change day-1. We further investigate the effect of light dilution on the fitted impact parameter and find that less than 1% of additional light is sufficient to explain the seasonal variation seen in the Kepler quarter data. We then extend our precession analysis to the phase curve data from which we report a rate of change day-1. This value is consistent with that of the transit data at a lower significance and provides the first evidence of spin-orbit precession based solely on the temporal variation of the secondary eclipse.

Original languageEnglish
Article number13
JournalAstronomical Journal
Issue number1
Publication statusPublished - 13 Dec 2017


  • planets and satellites: individual (Kepler-13, KOI-13)
  • stars: rotation
  • techniques: photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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