Exoplanets as Probes of Stellar Activity

Continuous light curves provided by the Kepler and CoRoT missions contain immense information on both stellar variability and exoplanets. We have developed a new technique to infer distribution of active regions in both longitude and latitude on the stellar surface (stellar images) from continuous light curves. This allows us to constrain stellar differential rotation, obtain butterfly diagrams, and investigate activity cycles. We further increase the spatial resolution of inferred stellar images by utilizing transit curves of exoplanets when they occult active regions (if available). We show also that exoplanets help to "see" active regions even when they are outside the planet transit path.