The slower rotation of planet-hosting stars revisited

Abstract Previous studies combined rotation periods derived from Kepler photometry, stellar parameters from previous Gaia Data Releases, and planet hosts from the NASA Exoplanet Archive to conclude that statistically planet-hosting stars rotate slower than stars without detected planets. Here, we revisit these studies by using similar Kepler rotational period sample, but with an updated Gaia DR3-based stellar parameter catalogue and an updated exoplanet catalogue. We apply minimal sample cuts in evolutionary state, metallicity, and distance, and then model the stellar rotation period as a function of effective temperature alone. For each star, we derive the ratio of its observed period to the temperature-expected period, and compare the ratio distributions for the planet-host and non-host stars. For periods shorter than 20 d, the planet-host distribution of this ratio is shifted towards longer periods; the period-ratio median is ∼15% larger for hosts than for non-hosts (pKS = 2.4 × 10−4). We also examine the recently published TESS All-Sky Rotation Survey (TARS) and find a similar trend. However, the strongly structured period distribution precludes a robust comparison between the host and the non-host stars. Therefore, the updated analysis, using more robust stellar and planetary parameters, recovers the previously reported association, strengthening the case for a genuine connection between stellar rotation and planet occurrence.