Challenges of Modelling Wolf-Rayet stars: Prescribed and Dynamically Consistent Winds

Abstract

Wolf-Rayet stars typically form most of their spectrum far out in their optically thick stellar winds. Due to this, accurately modelling the wind regime of these stars is crucial to determine their characteristics. The current wind modelling relies on a prescribed β -law for the velocity structure, of which observational evidence shows that not all Wolf-Rayet stars adhere to the standard β = 1 velocity law. By computing and comparing Wolf-Rayet star models with different β -laws, we show that the velocity structure strongly influences the emergent spectrum of these stars. While the more appropriate dynamically consistent modelling gives physically more accurate velocity descriptions, the prescribed velocity law models have significantly lower computational load but the effects of different β -laws need to be taken into account.