Project Details
Projekt
Cosmic ray production and transport in astrospheres
Applicant
Dr. Klaus Scherer
Subject Area
Astrophysics and Astronomy
Term
from 2012 to 2019
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 232615537
One paradigm concerning galactic cosmic ray spectra is that they are created in violent events, like supernova explosions. Recently, we have demonstrated that Sun-like stars can contribute to the lower energy range of the cosmic ray proton spectrum, by creating so-called anomalous cosmic rays (ACRs) in their outer astrospheres from originally interstellar neutral atoms. The main goal of this proposal is to continue and extend this approach, i.e. to model, based on observations, astrospheres (interstellar bubbles) and their ACR production for cool (F,G,K, and M) as well as for hot (O and B) stars located in different interstellar environments. Thus, we will, for the first time, quantify the contribution of cool stars to the low energy (GeV) range of cosmic rays, and give a quantitative estimate for the middle energy (TeV) range produced in astrospheres (interstellar bubbles) of hot stars. To do so, we will for the first time, incorporate not only cooling and heating terms in the energy equation of hot stars, but also consider the mass,- momentum-, and energy loading in the Euler equations self-consistently. For the latter the ionization reactions, like charge exchange between different atoms and ions, as well as the electron impact and photoioniziation will be included into the BoPo-code. Thus after modeling the large scale structure of astropheres, we will self-consistently determine the large scale anomalous cosmic ray flux and its leakage into the interstellar medium. The proposed research is timely, because it offers explanations to the recent observations of single ionized H3 regions, as well as the origin of cosmic rays in the TeV range. Such observations were recently made by the large area telescopes, like IceCube among others, and gamma-ray observatories.As an inherent result of the model we will provide the cosmic ray and neutral hydrogen fluxes inside the astrospheres of cool stars, possibly hosting exoplanets in habitable zones. All results will be made available on a public server at the Ruhr-Universität Bochum.
DFG Programme
Research Grants
International Connection
Austria, New Zealand, South Africa
