Climatological and UV-based Habitability of Possible Exomoons in F-star Systems

TL;DR

This study assesses the potential habitability of exomoons around F-type stars by analyzing UV radiation effects on DNA, considering planetary orbits and stellar environments, to identify conditions conducive to life.

Contribution

It introduces a combined climatological and UV-based framework for evaluating exomoon habitability around F-star systems, considering diverse orbital eccentricities and stellar UV environments.

Findings

DNA damage varies significantly across systems.

High orbital eccentricity increases DNA damage.

Some systems exhibit UV conditions exceeding Earth's early levels.

Abstract

We explore the astrobiological significance of F-type stars of spectral type between F5 V and F9.5 V, which possess Jupiter-type planets within or close to their climatological habitable zones. These planets, or at least a subset of those, may also possess rocky exomoons, which potentially offer habitable environments. Our work considers eight selected systems. The Jupiter-type planets in these systems are in notably differing orbits with eccentricities between 0.08 (about Mars) and 0.72. We consider the stellar UV environments provided by the photospheric stellar radiation, which allows us to compute the UV habitable zones for the systems. Following previous studies, DNA is taken as a proxy for carbon-based macromolecules following the paradigm that extraterrestrial biology might be based on hydrocarbons. We found that the damage inflicted on DNA is notably different for the range of systems studied, and also varies according to the orbit of the Jupiter-type planet, especially for systems of high ellipticity, as expected. For some systems excessive values of damage are attained compared to today's Earth or during the Archean eon. Considering that the detection of exomoons around different types of stars will remain challenging in the foreseeable future, we view our work also as an example and template for investigating the combined requirements of climatological and UV-based habitability for exosolar objects.