Talk

Spot modelling of Kepler-17: a planet-hosting star with solar-like differential rotation and a possible Rieger-like cycle

Antonino Francesco Lanza, INAF-Osservatorio Astrofisico di Catania

Maximum entropy spot modelling has recently been applied to more than 1500 days of Kepler photometry of the planet-hosting star Kepler-17 that is accompanied by a hot Jupiter with an orbital period of 1.486 days. It is a G2V star with a mean rotation period of 12 days which makes it a very interesting target for solar-stellar connection studies, especially to understand magnetic activity in the young Sun. By modelling starspots occulted during transits and comparing them with the spots mapped from the out-of-transit light curve, we derive information on the sign of differential rotation, that is found to be solar-like, and a lower limit for its amplitude, that is somewhat dependent on the assumptions of the spot model. There is also evidence of a short-term cycle in the total spotted area with a period of about 48 days and a significance of 5 percent. It could be analogous to the solar Rieger cycles and to a cycle of about 29 days observed in CoRoT-2 [This presentation will be based on Lanza et al. 2019, A&A 626, A38].