The clockwork is moving on -- a combined analysis of TESS and Kepler measurements of Kepler-13Ab

Abstract

Kepler-13Ab (KOI-13) is an exoplanet orbiting a rapidly rotating A-type star. The system shows a significant spin-orbit misalignment and a changing transit duration most probably caused by the precession of the orbit. Here we present a self-consistent analysis of the system combining {\it Kepler} and TESS observations. We model the light curves asssuming a planet transits a rotating oblate star which has a strong surface temperature gradient due to rotation-induced gravity darkening. The transit chord moves slowly as an emergent feature of orbital precession excited by the oblate star with a decline rate in the impact parameter of $\mathrm{d}b/\mathrm{d}t=-0.011/\mathrm{yr}$, and with an actual value of $b=0.19$ for the latest TESS measurements. The changing transit duration that was measured from {\it Kepler} Q2 and Q17 quarters and the TESS measurements indicates a linear drift of the impact parameter. The solutions for the stellar spin axis suggest a nearly orthogonal aspect, with inclination around $100^{\circ }$.

5 pages, 4 figures, 1 table; accepted by MNRAS

References in corpus (7)

• The Transiting Exoplanet Survey Satellite
• Atmospheric Characterization of the Hot Jupiter Kepler-13Ab
• Properties of analytic transit light curve models
• A Misaligned Prograde Orbit for Kepler-13 Ab via Doppler Tomography
• Spin-Orbit Angles of Kepler-13Ab and HAT-P-7b from Gravity-Darkened Transit Light Curves
• Spin-Orbit Misalignment and Precession in the Kepler-13Ab Planetary System
• Rapid rotators revisited: absolute dimensions of KOI-13

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• Revisiting the Kepler field with TESS: Improved ephemerides using TESS 2min data
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• Revisiting the Transit Timing Variations in the TrES-3 and Qatar-1 systems with TESS data
• Rapidly rotating stars and their transiting planets: KELT-17b, KELT-19Ab, and KELT-21b in the CHEOPS and TESS era
• Converting the sub-Jovian desert of exoplanets to a savanna with TESS, PLATO and Ariel
• 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