Investigation of the Influence of Stellar Particle Events and Galactic Cosmic Rays on the Atmosphere of TRAPPIST-1e

The launch of the James Webb Space Telescope (JWST) in December 2021 opens up the possibility of studying the composition of exoplanetary atmospheres in habitable zones, such as TRAPPIST-1e, in the near future. With the help of numerical models of the exoplanetary atmospheres, the observations and the processes behind them can be better understood and interpreted (Herbst et al., 2022). We investigate the influence of stellar energetic particles (SEPs) and galactic cosmic rays (GCRs) on the atmospheric chemistry of exoplanets around a very active M-star using the ion chemistry model ExoTIC. In collaboration with the University of Kiel and DLR Berlin, we perform model experiments with different N₂ or CO₂ dominated atmospheres, depending on the initial CO₂ partial pressure, as well as humid and dry conditions (Wunderlich et al., 2020), taking into account the ionization rates for such events. A further specification regarding the scenarios results from the distinction between dead and alive atmospheres, whose atmospheric composition is characterized by a lower or higher oxygen fraction in the initial conditions. Within ExoTIC we can calculate the impact of the ionization events on these atmospheres both as a single and as a series of events with different strengths. Preliminary results show a significant impact of SEP events on the chemical composition of the atmosphere, including biosignatures such as O₃ . The strength and structure of these impacts depend on the composition of the starting atmosphere, in particular on the availability of oxygen as well as nitrogen and water vapour.