POSTER PAPER 9.08
Turbulent Motions with Finite Correlation Length in the Winds of K and
M Supergiants
R. B. Boeger, R. Baade, M. Hegmann, D. Reimers
Institute: Hamburger Sternwarte, Universitat Hamburg
Institute: Institut fuer theoretische Physik der Universitat
Frankfurt am Main
Contact Email: rboeger@hs.uni-hamburg.de
Abstract:
High resolution spectra of lines formed in the wind of evolved late-type
stars suggest that the usual microturbulent assumption is not adequate to
describe the nonthermal motions. We present a NLTE radiative transfer scheme
that incorporates turbulent velocity fields with finite correlation length.
In this approach we consider the turbulent velocity and consequently the
intensity to be stochastic variables. This leads to a generalized equation of
transfer having the form of a Fokker-Planck equation. In a first
application we demonstate the general effects of velocity fluctuations on the
line formation in expanding atmospheres.
Index Keywords: Line Formation
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Manuscript submitted: 2001-Sep-06
"The Future of Cool-Star Astrophysics", 2003, Eds. A. Brown,
G. M. Harper, & T. R. Ayres.
Proceedings of 12th Cambridge Workshop on Cool Stars, Stellar Systems,
& The Sun,
© 2003 University of Colorado.