Interaction of extrasolar planets with their host star

Abstract

Currently a total of nearly 300 planets, from more than 800 detected, are known to eclipse their host star. During one of these transits, the planet may occult a spot on the photosphere of the star, causing small variations in its light curve. By detecting the same spot in a later transit, it is possible to estimate the stellar rotation period, similarly to what Galileo did for the Sun nearly four centuries ago. Some stars with planets that were detected by the Kepler and CoRoT satellites have been analyzed and their rotation periods and differential rotation determined. Results from the comparison between the rotation period of the star and the planet's orbital period showed the existence of resonances between these periods. In this work we intend to study which interaction mechanism is responsible for this synchronicity. Two types of mechanisms are proposed in the literature and will be tested: electromagnetic interaction between the stellar and planetary fields and gravitational interaction, or tidal effects. (AU)