Name/Affiliation: Jeffrey Linsky (University of Colorado)
Predicting the Extreme-UV and Lyman-alpha Fluxes Received by Exoplanets from their Host Stars
Extreme-UV radiation from the chromospheres, transitions regions, and coronae of host stars (spectral types F, G, K, and M) ionize and heat the outer atmospheres of exoplanets leading to mass loss that is observed during transits. Lyman-alpha emission from host stars controls the photochemistry of water, CO2, methane, and other important molecules in exoplanet atmospheres. Both types of radiation are largely absorbed by the interstellar medium and must be reconstructed or estimated to understand the radiation environment of exoplanets. We describe several techniques for reconstructing the intrinsic Lyman-alpha radiation and for predicting the EUV flux. Solar models and satellite observations (HST, FUSE, and EUVE) provide tests for the feasibility of these methods.