Detecting extraterrestrial oxygen with the ELT

Among the many exciting capabilities of the upcoming Extremely Large Telescope (ELT) is its potential to search for biosignatures in the atmospheres of terrestrial exoplanets, and by extension, probe for extraterrestrial life. In particular, the A-band of molecular oxygen at 7600 Angstroms is an ideal biosignature to target with ground-based observations and cross-correlation retrieval due to its spectral isolation and resolvability into sharp lines at high spectral resolution (R ~ 100,000). Therefore, understanding our ability to detect this feature in terrestrial planets’ atmospheres with the ELT is of great importance to the search for life beyond the Solar System. We simulate ELT observations of the transmission spectrum of an Earth-twin transiting a late-type M-dwarf in the habitable zone to determine detection thresholds for the oxygen A-band. By utilizing Very Large Telescope spectroscopy with flux noise comparable to that of future ELT observations of typical, late-type M-dwarfs, our simulations account for both flux and systematic noise, improving upon the accuracy of previous simulations. I will present our latest results of oxygen detectability using the ELT, and their implication for the search for biosignatures and extraterrestrial life.

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