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Paper: Spectral Synthesis of Rapidly Rotating Massive-Stars
Volume: 464, Circumstellar Dynamics at High Resolution
Page: 161
Authors: Ribeiro, J. M.; Carciofi, A. C.
Abstract: Here we report on recent developments on the HDUST radiative transfer code, with the goal of making accurate spectral synthesis for rapidly rotating massive stars. The code treats correctly the geometrical deformation of the rotating star and the non-uniform flux distribution due to the von Zeipel effect. This effect, also known as gravitational darkening, arises from the fact that the radiative flux at one point of the photosphere is (roughly) proportional to the local effective gravity. Because of the high rotation rate of the star, each latitude has, then, a different effective temperature. In the current version of the code, HDUST uses, for each latitude in the stellar photosphere, a Kurucz model atmosphere for the appropriate log (g) and effective temperature. The Kurucz spectra, however, are of very low resolution and do not describe accordingly the photospheric line profiles. Because of this, the code cannot synthesize accurate line profiles for rotating stars. In this work we propose to extend HDUST to include, for each latitude bin, the appropriate phostopheric line profile. For that, an interface between HDUST and the model atmosphere code TLUSTY will be built. When ready, the new code will allow us to perform accurate line profile synthesis of fast-spinning stars, including the effects arising from the presence of a circumstellar disk.
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