Can hydrogen coronae be inferred around a CO2-dominated exoplanetary atmosphere?

摘要: Abstract To date, almost 20% of the known exoplanets are in Earth/super-Earth mass regime, and more have to be confirmed, as they represent about 40% Kepler candidates. Some these planets like Kepler-11 system exhibit very low densities, which can explained by a high content water (“waterworlds”) or large hydrogen/helium atmosphere. Recent theoretical work has been done explain how planet could sustain such an atmosphere for several Gyr. On other hand, some authors proposed methods based on transit absorption spectroscopy detect characterize possible atmospheres. In this paper, we explore possibility inferring presence atomic hydrogen corona looking at its influence thermospheric emissions lower CO 2 Two emission lines studied details, namely O( 1 S  −  D ) “green-line” 557 nm + ( B Σ u - X Π g UV-doublet around 289 nm. We use 1D transport code coupled radiative transfer model calculate contrast with parent star two lines. find that case telluric 1 AU from G-type 0.03 AU active M dwarf, contrasts between too observed current planned instruments.