Investigating Cosmic-Ray Induced Radiation in Exoplanetary Environments

Abstract The study of cosmic rays (CRs) and their interactions with exoplanetary atmospheres and stellar environments can provide essential insights into the habitability and atmospheric chemistry of these distant worlds. For instance, on Earth, radiation from cosmic rays constitutes only about 10 percent of the total radiation exposure at ground level, but this percentage can be significantly higher for planets orbiting stars close to cosmic ray sources. Furthermore, the modulation of cosmic rays varies considerably among different stars. This research focuses on modelling the modulation of CRs by various stellar types, particularly F, G, K, and M stars, to understand the impact on exoplanets in their habitable zones. Employing an analytical one-dimensional model of the Cosmic Ray Transport Equation, which allows us to study a wide range of parameters, we analyse how different stellar parameters, such as wind speed and magnetic field strength, influence the cosmic ray environment. The developed model simulates the cosmic ray spectra and mean free path, considering factors like the star’s relative motion through the interstellar medium. This work aims to contribute to the understanding of radiation conditions on exoplanets, which is crucial for assessing their potential to support life. It offers a preliminary but meaningful exploration into the complex interactions between cosmic rays and exoplanetary environments, shedding light on factors that might influence the habitability of these alien worlds.