Modelling atmospheric biosignature and climate responses for Earth-like planets orbiting M-dwarf stars

Abstract

We investigate the atmospheric responses in climate and photochemistry in order to assess habitability and potential biosignatures for Earth-like planets orbiting M-dwarf stars. We apply the coupled climate-chemistry column model 1D-TERRA which features a flexible climate model applicable over a wide range of atmospheric conditions ranging from Mars-like to Venus and which includes a comprehensive chemical network containing several thousand gas-phase reactions. Our numerical scheme is part of a model suite which includes a parameterization of air shower events including the influence of both ion and gas phase chemistry coupled with climate effects. Results present the influence upon commonly assessed chemical species such as oxygen, ozone, methane and nitrous oxide and we investigate their role to act as potential biosignatures over a range of external conditions including spectral type and activity.