Energetic radiation from exoplanet hosts: The most detailed study of our nearest host star Proxima Centauri

The conditions in the atmosphere of exoplanets, and therefore for the formation of life, depend strongly on the host star’s irradiation spectrum. The energy input into the atmosphere by stellar photons controls the formation and destruction of molecules, and may even lead to the evaporation (loss) of a significant fraction of the atmosphere. These processes, however, depend critically on the shape of the irradiation spectrum (the stellar SED). In particular, the formation of biosignatures depends on the stellar high-energy spectrum (photons with wavelengths shortwards of ~3000 Angstrom). However, the high-energy part of the irradiation spectrum is poorly known for the most common type of exoplanet hosts, namely M dwarfs.
The main objective of this project is therefore to provide the most accurate high-energy spectrum of an M dwarf planet host. To this end, data spanning from the X-ray to the optical regime were obtained for the nearest exoplanet host Proxima Centauri. By analyzing these data, we will (1) determine the high-energy spectrum of Proxima Centauri, (2) characterize the physical properties of the emitting plasma, (3) measure the flare rate and properties, and (4) reconstruct the important EUV range, which is unobservable due to interstellar absorption, but critical for the energy input into the upper planetary atmosphere.