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EP: Fachverband Extraterrestrische Physik
EP 2: Exoplanets and Astrobiology
EP 2.4: Talk
Monday, March 20, 2023, 17:15–17:30, ZEU/0160
Deciphering Dayglow as Biosignature of Planet Earth — •Katharina Uhlmannsiek1, Michael Sterzik1, Claudia Emde2, and Stefano Bagnulo3 — 1ESO, Garching, Germany — 2Institute for Meteorology LMU, München, Germany — 3Armagh Observatory, Belfast, UK
Biosignatures in the near-infrared spectrum of Earth's atmosphere include the simultaneous presence of H2O, O2 and CH4 molecular absorption bands, but also abundant skyline emission features caused by chemo-photolytic reaction networks of Oxygen in the upper atmosphere such as OH. New infrared spectra of Earthshine were obtained with the CRIRES+ instrument at the VLT and achieve a high spectral resolution of R > 100 000. Thus, narrowband features of day- and nightglow emission (e.g. OH, O2) can be resolved. We compare airglow lines caused by different mechanisms, and try to discern day- and nightglow from contaminating atmospheric transmission. Earthshine spectra consist of the spatially integrated light of the illuminated Earth and Earth's atmosphere and are therefore considered analogous to direct observations of exoplanets. Hence, tracing biosignatures in our high-resolution CRIRES+ observations of Earthshine opens a novel window for the detection of biosignatures of Earth-like planets.