Habitability in the Environments of Main-Sequence Stars

Professor Manfred Cuntz

University of Texas at Arlington

Abstract: In this presentation, I will explore the general possibility of exobiology for different types of stars, especially main-sequence stars. I will take into account aspects of stellar evolution, including nuclear evolution (which often entails considerable changes in the stellar luminosity) and magnetic evolution. The latter is relevant in regard to the circumstellar UV environment, which may have both supportive and destructive significances for the existence and sustainability of life. Moreover, I will consider the astrobiological significance of F-type main-sequence stars, which usually receive little attention by the scientific community. For those stars, it is found that the estimated biological damage for planets at Earth-equivalent positions is noticeably higher than for planets around solar-like stars (but the results are not hopeless), and that there are intricate relationships for the time-dependence of damage during the stellar main-sequence evolution. Intriguing aspects pertaining to habitable environments are also identified for stellar binary systems (which are dominant compared to single stars), where the existence of habitable regions requires additional consideration owing to stellar radiative and gravitational constraints.