Long-term Variations in the Orbital Period of Hot Jupiters from Transit-timing Analysis Using TESS Survey Data

Abstract

Abstract Many hot Jupiters may experience orbital decays, which are manifested as long-term transit-timing variations. We have analyzed 7068 transits from the Transiting Exoplanet Survey Satellite (TESS) for a sample of 326 hot Jupiters. These new mid-transit-time data allow us to update ephemerides for these systems. By combining the new TESS transit-timing data with archival data, we searched for possible long-term variations in the orbital period in these hot Jupiters using a linear and a quadratic ephemeris model. We identified 26 candidates that exhibit possible long-term variations of the orbital period, including 18 candidates with decreasing orbital periods and eight candidates with increasing orbital periods. Among them, 12 candidates failed our leave-one-out cross validation test and thus should be considered to be marginal candidates. In addition to tidal interaction, alternative mechanisms such as apsidal precession, the Rømer effect, and the Applegate effect could also contribute to the variations during the observed period. The ephemerides derived in this work are useful for scheduling follow-up observations for these hot Jupiters in the future. The Python code (PdotQuest, https://github.com/AeoN400/PdotQuest) used to generate the ephemerides is made available online.