Boeger, Roger

Contact Email: rboeger@hs.uni-hamburg.de
Institute: Hamburger Sternwarte, Universität Hamburg
First Coauthor: Robert Baade
Institute: Hamburger Sternwarte, Universität Hamburg
Second Coauthor: Michael Hegmann
Institute: Institut für Theoretische Physik der Universität
Frankfurt am Main
Presenting Thesis: Yes
Subject Area: Stellar Atmospheres, Circumstellar Material
Waveband: Ultraviolet
Technique: Computational Astrophysics
Presentation: Poster Display
Title: Turbulent motions with finite correlation length in the winds of K and M supergiants
Abstract: Turbulent motions in the extended envelopes of K and M Supergiants are generally treated in the microturbulent limit. High resolution spectra suggest that this approach is not adequate to describe the non-thermal stochastic motions observed in the winds of these stars. We present a NLTE radiative transfer model for a spherically symmetric atmosphere that incorporates turbulent velocity fields. The overall property of the wind is assumed to follow the common $\beta$ power law. The turbulent velocity component is described in terms of a stochastic variable which line of sight behavior corresponds to a Markov process. Consequently the intensity also becomes a stochastic variable. As a result the generalized equation of radiative transfer has the form of a Fokker-Planck equation. 3rd Co-Author: Dieter Reimers, Hamburger Sternwarte, Universität Hamburg