High Resolution Spectral Discriminants of Ocean Loss for M Dwarf Terrestrial Exoplanets

In the near future, ground based spectrometers on the Extremely Large class of telescopes will be able to detect exoplanet atmosphere with unprecedented resolution. These tools are favorable for biosignature detection since high resolution spectra allow for characterization of atmospheric constituents. One of the most well known potential biosignature gases is oxygen since it is produced in high levels by photosynthesis. However, planetary processes such as ocean loss can also generate large amounts of atmospheric oxygen leading to potential false positive characterization. Here we show that O₂-O₂ collisionally induced absorption at O₂ bands can be used to differentiated between a photosynthetic biosphere and a high oxygen atmosphere produced by ocean loss.