Contributed Talk - Splinter CosmicRays

Monday, 13 September 2021, 09:15   (virtual Cosmic)

Constraining the energetic particle flux of young stars during the period of planet formation.

Christian Rab
Max Planck Institute for Extraterrestrial Physics, LMU - Universit√§ts-Sternwarte M√ľnchen

High energy ionization sources such as X-rays, cosmic rays and stellar energetic particles (stellar cosmic rays, SP) can ionize molecular hydrogen, the most abundant chemical species in the environment of young stars. Therefore, they play a crucial role in the chemistry and evolution of the circumstellar environment of young stars. We use the radiation thermo-chemical disk code ProDiMo (PROtoplanetary DIsk MOdel) to model the impact of those high-energy ionization sources on the chemistry of the circumstellar environment and, in particular, the planet-forming disk. The model includes X-ray radiative transfer and makes use of different particle transport models to calculate the individual molecular hydrogen ionization rates in the disk and envelope of young stars. We study the impact on the chemistry via the ionization tracers such as HCO+ and N2H+ and produce synthetic observables for observations in the sub-mm wavelength regime (e.g. ALMA). We argue that spatially resolved observations of molecular ions combined with detailed models allow for disentangling the contribution of the individual high-energy ionization sources. This opens up the possibility of measuring the SP flux of young stars via observations of their circumstellar environment and providing constraints for particle transport models (i.e. the importance of magnetic fields).