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

• Applicant: Dr. Christian Schneider
• Subject Area: Astrophysics and Astronomy
• Term: from 2017 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 361764860

Proxima Cen b is the nearest exoplanet to Earth - and possibly habitable. The latter, however, depends critically on the illumination by high-energy radiation from its host star, which is an active M dwarf. No models exist that allow a sufficiently accurate prediction of the stellar high-energy spectrum to answer the question of habitability without detailed observations in the X-ray and UV regimes.We have organized the so far most extensive X-ray to UV observing campaign of Proxima Cen to simultaneously measure the complete high-energy spectrum with unprecedented detail. This includes a massive 175 ks of Chandra X-ray coverage using the Low Energy Transmission Grating Spectrometer covering wavelengths from about 2 - 175 A, accompanied by five simultaneous orbits of Hubble Space Telescope UV data as well as coverage at higher energies with the ASTROSAT satellite, plus supporting ground-based data. The goals of this project are twofold: First, we will create broad-band spectral energy distributions for different activity levels of Proxima Cen to enable a detailed assessment of the habitability of our nearest exoplanetary neighbor and, second, to use the proximity of the target to advance our understanding of magnetic activity on low-mass stars, which likely outnumber other types of planet hosts in our Galaxy. Hence, to better understand the astrophysical conditions necessary to harbor life and how common these are in our Milky Way, i.e., directly addresses the one of the main questions posed in the announcement of the Priority Programme "Exploring the Diversity of Extrasolar Planets" (SPP 1992).

• DFG Programme: Priority Programmes
• Subproject of: SPP 1992: Exploring the diversity of extrasolar planets