2013msao.confE.104U
3D Simulations of Magnetic Massive Star Winds
ud-Doula, Asif ( Penn State Worthington Scranton ); Sundqvist, Jon ( Department of Physics and Astronomy, University of Delaware ); Owocki, Stan ( Department of Physics and Astronomy, University of Delaware ); Petit, Veronique ( Department of Physics and Astronomy, University of Delaware ); Townsend, Richard ( University of Wisconsin ) show affiliations
Massive Stars: From α to Ω, held 10-14 June 2013 in Rhodes, Greece; Online at http://a2omega-conference.net, id.104
Published in Jun 2013
Due to computational requirements and numerical difficulties associated with coordinate singularity in spherical geometry, fully dynamic 3D magnetohydrodynamic (MHD) simulations of massive star winds are not readily available. Here we report results of the first such a 3D simulation using specific parameters representing the prototypical slowly rotating magnetic O star Î̧^1 Ori C, for which centrifugal and other dynamical effects of rotation are negligible. The computed global structure in latitude and radius resembles that found in previous 2D simulations, with unimpeded outflow along open field lines near the magnetic poles, and a complex equatorial belt of inner wind trapping by closed loops near the stellar surface, giving way to outflow above the Alfven radius. In contrast to this previous 2D work, the 3D simulation described here now also shows how this complex structure fragments in azimuth, forming distinct clumps of closed loop infall within the Alfven radius. Applying these results in a 3D code for line radiative transfer, we show that emission from the associated 3D 'dynamical magnetosphere' matches well the observed Hα emission seen from Î̧^1 Ori C, fitting both its dynamic spectrum over rotational phase and the observed level of cycle-to-cycle stochastic variation.
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