Astrospheres and cosmic rays

Abstract

Ionization plays a key role in the formation of stars, planets and planetary atmospheres. Cosmic rays (CR) are the main source of ionization, therefore it is important to estimate fluxes of galactic and stellar cosmic rays (GCR and SCR) for different stages of evolution of stars and planetary systems. Radiation conditions on exoplanets might be important for the origin and development of life. We present a review of the current state of knowledge of astrospheres and their interactions with GCR and SCR. We pay special attention to estimates of radiation conditions near exoplanets recently discovered in a habitable zone of their hosting stars.