The first public data release from the Kepler Space Telescope contained over 156,000 stars which had been monitored continuously for approximately 33 days. With continuous photometric monitoring and unprecedented ultra-high precision, the Kepler dataset is an splendid resource for investigating stellar rotation (and age) via starspots as well as for investigating starspot fractional coverage and distributions, starspot lifetime and differential rotation as a function of spectral type and rotation/age. Here, we narrowed our focus to the 306 planetary candidates, mostly main sequence late F, G and K stars, released during June 2010 (see Boruki et al. 2010). This is an attractive data set for the study of starspots properties since these stars host transiting planets with orbital planes almost exactly aligned with our line-of-sight and will generally have the host stars’ rotation axes perpendicular to the planetary orbital plane. Thus, the inclination of the star’s rotation axis can be assumed known and should (in most cases) be at right angles to our line-of-sight. Using a Lomb-Scargle Periodogram analysis, we have extracted reliable rotation periods and spot coverages for stars which showed evidence for starspots. From the measured rotation periods, we were able to determine, empirically, the age of the stellar system (using Villanova rotation-age relations) and investigate the potential tidal evolution of the planet-star system. However, we found good evidence that rotation-age relations do not apply to stars that host short-period, Jupiter sized planets. The aforementioned stars show a definite tendency towards star-rotation-planet orbital synchronization. The initial results of this exploratory program will be discussed.
This project was initiated at the 2010 Sagan Exoplanet Summer Workshop hosted by NExScI at Caltech. We wish to thank NASA and the organizers of the workshop – in particular Dawn Gelino and Carolyn Brinkworth. EG wishes also to acknowledge support from NSF/RUI Grant AST-10-09903.