Tides and Magnetic Fields in Hot Jupiter Systems
Evgenya Shkolnik

Hot Jupiters, located only a few stellar radii from their parent stars, provide a laboratory in which we can study fundamental system parameters including planetary magnetic fields, a key component to understanding the planet’s internal structure and atmospheric conditions. Over a dozen studies of hot Jupiter systems have independently converged on the same scenario: a short-period planet can induce activity on the photosphere and upper atmosphere of its host star, making the star itself a probe of its planet. This makes star-planet interactions (SPI) currently the most promising way to study exoplanetary magnetic fields. In addition, strong tidal interactions between the hot Jupiter and its star will increase the stellar rotation rate as well as the global stellar activity level, provided that the planet migrated early on in the system's history. Studying the tidal and magnetic interactions in such planetary systems builds our understanding of the formation, migration and evolution of close-in planets.