Contributed Talk - Splinter Exoplanets

Thursday, 24 September 2020, 16:20   (virtual room D)

INCREASE - A model suite to study the INflucence of Cosmic Rays on Exoplanetary AtmoSpherEs

K. Herbst, J.L. Grenfell, M. Scheucher, M. Sinnhuber, F. Wunderlich
Christian-Albrechts-Universität zu Kiel, TU Berlin, DLR Berlin, Karlsruher Institut für Technologie

The first opportunity to detect indications for life outside of the Solar System may be provided already within this decade. However, the harsh stellar radiation and particle environment of planets in the habitable zone of the favored target stars (K- and M-stars) could lead to photochemical loss of atmospheric biosignatures. A self-consistent model suite of combined state-of-the-art tools has been developed to study the impact of the radiation and particle environment (cosmic and stellar rays) on atmospheric particle interactions, composition, and climate interactions. This has been employed for an Earth-like N2-O2 atmosphere (Herbst et al., 2019) and a feasible planet with an N2-O2-CO2 atmosphere around Proxima Centauri (Scheucher et al., 2020). In a next step, we will extend our model studies to a wide range of possible exoplanetary atmospheres and stellar environments to tackle the following questions: (1) What processes determine whether (rocky) worlds around cooler stars can retain their atmospheres? (2) How do different atmospheres evolve for cool star systems?, and (3) How do results from our study compare with observations? In particular, we will investigate the impact of stellar activity on planetary climate, atmospheric escape, density and composition, surface radiation, the planets radiation dosage, and the impact on potential observables. Bibliography Herbst et al., A&A, 631, A101 (2019), doi:10.1051/0004-6361/201935888 Scheucher et al., ApJ, 893:12 (2020), doi:10.3847/1538-4357/ab7b74