Abstract

3-D Monte Carlo radiative transfer calculation of resonance line formation in the inhomogeneous expanding stellar wind

Brankica Šurlan (Astronomical Institute Ondřejov)

W.-R. Hamann - University of Potsdam, Germany J. Kubát - Astronomical Institute Ondřejov, Czech Republic L. M. Oskinova - University of Potsdam, Germany A. Feldmeier - University of Potsdam, Germany

The true mass-loss rates from massive stars are important for many branches of astrophysics. The stellar wind clumping must be incorporated in radiative transfer to correctly model the resonance lines, which are among the key diagnostics of stellar mass-loss rate. We developed a full 3-D Monte Carlo radiative transfer code for the inhomogeneous expanding stellar wind. For the first time realistic 3-D models that describe the dense as well as the tenuous wind components are used to model formation of resonance lines in a clumped stellar wind. Comparison with observed UV lines in spectra of hot stars provide important constrains on the true nature of clumping in massive star winds. Our new model demonstrates that to obtain empirically correct mass-loss rates based on the UV resonance lines, the wind clumping and its 3-D nature must be taken into account.