München 2019 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 6: Astrophysics I: Astrospheres

EP 6.3: Talk

Thursday, March 21, 2019, 12:45–13:00, HS 9

MHD-shock structures of astrospheres — •Klaus Scherer¹, Lennart Baalmann¹, Horst Fichtner¹, Jens Kleimann¹, Dominik Bomans², Kerstin Weis², and Stefan Ferreira³ — ¹Institut für theoretische Physik IV, Ruhr-Universität Bochum, 44780 Bochum, Germany — ²Astronomisches Institut, Ruhr-Universität Bochum, 44780 Bochum, Germany — ³Centre for Space Research, North-West University, 2520 Potchefstroom, South Africa

The interpretation of recent observations of bow shocks around O stars and the creation of corresponding models require a detailed understanding of the associated (magneto-)hydrodynamic structures, which will be discussed here. We discuss in detail the magnetohydrodynamic structures associated with stellar bow shocks, which are of high relevance for further studies of turbulence and cosmic-ray modulation. We describe in detail the fast- and slow-magnetosonic regions using the corresponding Mach numbers. We show that in O star astrospheres, distinct regions exist in which the fast, slow, Alfvénic, and sonic Mach numbers become lower than one, implying sub-slow magnetosonic, as well as sub-fast and sub-sonic flows.