Detecting biomarkers in exoplanetary atmospheres with a Terrestrial Planet Finder - art. no. 70101N

There are good reasons for extending the spectral range of observation to shorter wavelengths than currently envisaged for terrestrial planet-finding missions utilizing a 4-m, diffraction-limited, optical telescope. The angular resolution at shorter wavelengths is higher, so that the image of an exoplanet is better separated from that of the much brighter star. Due to the higher resolution, the exozodiacal background per resolution element is smaller, so exposure times are reduced for the same incident flux. Most importantly, the sensitivity to the presence of life on habitable exoplanets is increased over a hundred-fold by access to the ozone biomarker in the mid-ultraviolet. These benefits must be weighed against challenges arising from the faintness of exoplanets in the mid-UV. Here, we describe the benefits, technical challenges and some proposed solutions for detecting ozone in the atmospheres of Earth-like exoplanets.