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

Abstract

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. (2012) and Masuda (2015), reporting a rate of change $db/dt=(-4.1\pm 0.2)\times 10^{-5}$ 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 $db/dt=(-3.2\pm 1.3)\times 10^{-5}$ 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.

Accepted to AJ. 8 pages, 7 figures

References in corpus (26)

• emcee: The MCMC Hammer
• Analytic Lightcurves for Planetary Transit Searches
• Characteristics of planetary candidates observed by Kepler, II: Analysis of the first four months of data
• Efficient, uninformative sampling of limb darkening coefficients for two-parameter laws
• Kepler Input Catalog: Photometric Calibration and Stellar Classification
• Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments
• Revised Stellar Properties of Kepler Targets for the Quarter 1-16 Transit Detection Run
• Gravity darkening in rotating stars
• Large Amplitude Variations of an L/T Transition Brown Dwarf: Multi-Wavelength Observations of Patchy, High-Contrast Cloud Features
• Changing Phases of Alien Worlds: Probing Atmospheres of Kepler Planets with High-Precision Photometry
• The Transit Light Curve Project. V. System Parameters and Stellar Rotation Period of HD 189733
• Optical Phase Curves of Kepler Exoplanets
• Transit Lightcurves of Extrasolar Planets Orbiting Rapidly-Rotating Stars
• Asymmetric transit curves as indication of orbital obliquity: clues from the late-type dwarf companion in KOI-13
• Atmospheric Characterization of the Hot Jupiter Kepler-13Ab
• Variability in the Atmosphere of the Hot Giant Planet HAT-P-7 b
• Measurement of the Spin-Orbit Misalignment of KOI-13.01 from its Gravity-Darkened Kepler Transit Lightcurve
• Determination of Three-dimensional Spin-orbit Angle with Joint Analysis of Asteroseismology, Transit Lightcurve, and the Rossiter-McLaughlin Effect: Cases of HAT-P-7 and Kepler-25
• A Misaligned Prograde Orbit for Kepler-13 Ab via Doppler Tomography
• The Brown dwarf Atmosphere Monitoring (BAM) Project I: The largest near-IR monitoring survey of L- & T-dwarfs
• Spin-orbit resonance, transit duration variation and possible secular perturbations in KOI-13
• Spin-Orbit Angles of Kepler-13Ab and HAT-P-7b from Gravity-Darkened Transit Light Curves
• Investigation of systematic effects in Kepler data: Seasonal variations in the light curve of HAT-P-7b
• Mapping a star with transits: orbit precession effects in the Kepler-13 system
• The Brown-dwarf Atmosphere Monitoring (BAM) Project II: Multi-epoch monitoring of extremely cool brown dwarfs
• Rapid rotators revisited: absolute dimensions of KOI-13

Cited by in corpus (18)

• Stellar obliquities in exoplanetary systems
• Two new HATNet hot Jupiters around A stars, and the first glimpse at the occurrence rate of hot Jupiters from TESS
• Decaying Orbit of the Hot Jupiter WASP-12b: Confirmation with TESS Observations
• HATS-70b: A 13 Mjup brown dwarf transiting an A star
• Spi-OPS: Spitzer and CHEOPS confirm the near-polar orbit of MASCARA-1 b and reveal a hint of dayside reflection
• The clockwork is moving on -- a combined analysis of TESS and Kepler measurements of Kepler-13Ab
• Storms or Systematics? The changing secondary eclipse depth of WASP-12b
• The GAPS Programme with HARPS-N at TNG. XXXI. The WASP-33 system revisited with HARPS-N
• Orbital Stability and Precession Effects in the Kepler-89 System
• The SNR of a Transit
• Doppler Tomographic Measurement of the Nodal Precession of WASP-33b
• Nodal Precession of WASP-33b for Eleven Years by Doppler Tomographic and Transit Photometric Observations
• An Extreme-mass Ratio, Short-period Eclipsing Binary Consisting of a B Dwarf Primary and a Pre-main Sequence M Star Companion Discovered by KELT
• TESS Observations of the Hot Jupiter Exoplanet XO-6b: No Evidence of Transit Timing Variations
• Systematic search for long-term transit duration changes in Kepler transiting planets
• The phase curve of the ultra-hot Jupiter WASP-167b as seen by TESS
• The effects of stellar gravity darkening on high-resolution transmission spectra
• Characterizing the WASP-4 system with TESS and radial velocity data: Constraints on the cause of the hot Jupiter's changing orbit and evidence of an outer planet