München 2019 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 11: Astrophysics III: Stellar Astrophysics
EP 11.2: Vortrag
Freitag, 22. März 2019, 12:45–13:00, HS 19
Force-Free modelling of stellar magnetic fields — •Thomas Wiegelmann1 and Jörg Büchner2,1 — 1MPI für Sonnensystemforschung, Göttingen — 2Center for Astronomy and Astrophysics, Technical University Berlin
Exo-planets of dwarfs are easy to detect because of their close orbits. For having a habitable zone planets need shielding by a planetary magnetic field. Exo-planetary magnetospheres are shaped and influenced by the magnetic field and wind of their host-star. Therefor it is important to model the large scale structure of stellar magnetic fields, here a fast rotating M-dwarf. The surface magnetic field (intensity and orientation)is measured with Zeeman-Doppler imaging, a tomographic imaging technique. We extrapolate these measurements into stellar coronae with the help of a potential field source surface (PFSS) model and a nonlinear force-free field (NLFFF) model. We find that open field maps and the global magnetic field structure are very different between these models (much more than for solar applications). The investigated dwarfs contain a large amount of free energy which can cause huge flares.