Atmospheric Composition Retrieval from Transit Spectra of Terrestrial Exoplanets: A Feasibility Study using Earth Observations

Kurzfassung

For an assessment of the detectability of molecular concentrations from transit spectra of Earth-like exoplanets, occultation spectra observed by an operational Earth observation satellite mission have been modeled with a line-by-line infrared radiative transfer code (Schreier et al. 2014). Retrieval of atmospheric composition utilizing a nonlinear least squares fit of degraded spectra allows to infer detection limits for different spectral regions, resolution and noise levels. The fitted scaling factors of the molecular abundances in the atmosphere are very sensitive to changes in the resolution, which will therefore also be key for the retrieval of exoplanet atmosphere composition.