3D spectral synthesis and rotational line broadening
GEPI, CIFIST, Observatoire de Paris-Meudon, 5 place Jules Janssen, 92195 Meudon Cedex, France e-mail: Hans.Ludwig@obspm
Accepted: 6 May 2007
Context.Spectral synthesis calculations based on three-dimensional stellar atmosphere models are limited by the affordable angular resolution of the radiation field. This hampers an accurate treatment of rotational line broadening.
Aims.We aim to find a treatment of rotational broadening of a spherical star when the radiation field is only available at a modest number of limb-angles.
Methods.We apply a combination of analytical considerations of the line-broadening process and numerical tests.
Results.We obtain a method which is closely related to classical flux convolution and which performs noticeably better than a previously suggested procedure. It can be applied to rigid as well as differential rotation.
Key words: hydrodynamics / radiative transfer / stars: atmospheres / line: profiles / methods: numerical
© ESO, 2007