Stellar X-Ray-UV Coronal Activity and Its Impact on Planets

Planets spend their entire life within an environment predominantly shaped by the presence of a host star. Such stellar foreign frequently characterized by intense energy radiation and energetic stellar winds poses formidable constraints to planet evolution. Consequently, a comprehensive understanding of the star and its interaction with the planet is crucial to properly understand planetary processes and climate. The field of star-planet interaction is huge and involves different kinds of physics. This chapter directs its focus toward the high-energy domain, specifically addressing the impact of high-energy radiation on dynamic processes and the chemistry of exoplanets and on the role that atmosphere photoevaporation plays in shaping stellar activity.