Greifswald 2024 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 2: Planets in their Environment

EP 2.12: Vortrag

Dienstag, 27. Februar 2024, 18:15–18:30, ELP 1: HS 1.22

Investigation of the Influence of Stellar Energetic Particles (SEPs) on the Atmosphere of TRAPPIST-1e — •Andreas Bartenschlager¹, Miriam Sinnhuber¹, John Lee Grenfell², Nicolas Iro², Benjamin Taysum², and Konstantin Herbst³ — ¹KIT Karlsruhe — ²DLR Berlin — ³CAU Kiel

New instruments (JWST) open up the possibility of studying the composition of exoplanetary atmospheres in habitable zones. On explanets around very active M-stars like TRAPPIST-1, the impact of SEPs on the atmosphere plays an important role and is investigated with the ion chemistry model ExoTIC (Herbst et al., 2022). Within the INCREASE project, 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). A further specification is the distinction between dead and alive atmospheres, whose composition is characterized by initial lower/higher O₂ fractions. Further model development gives the possibility to simulate the ion chemistry’s impact on the atmospheric composition of multiple ionization events with different strengths and frequencies, based on the observed flaring frequency of TRAPPIST-1. Preliminary results show a significant impact of SEP events on the chemical composition of the atmosphere, including biosignatures such as O₃, especially in the recovery of the ozone layer after multiple SEP events. These changes have an impact on the observed transmission spectra. The strength and structure of these impacts depend on the initial composition, in particular on the availability of O₂, N₂ and H₂O.

Keywords: Exoplanetary Atmospheres; Stellar Energetic Particle events; Biosignatures