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

TL;DR

This paper presents a 3-D Monte Carlo radiative transfer model to study how inhomogeneities and velocity fields in stellar winds affect resonance line formation, crucial for accurate mass-loss rate estimates.

Contribution

It introduces a comprehensive 3-D MCRT code capable of modeling complex wind structures and velocity fields, improving the understanding of resonance line formation in stellar winds.

Findings

3-D density and velocity inhomogeneities significantly influence resonance lines.

Accounting for wind clumping is essential for reliable mass-loss rate measurements.

The model aligns well with observations, highlighting the importance of inhomogeneity effects.

Abstract

We study the effects of optically thick clumps, non-void inter-clump medium, variation of the onset of clumping, and velocity dispersion inside clumps on the formation of resonance lines. For this purpose we developed a full 3-D Monte Carlo Radiative Transfer (MCRT) code that is able to handle 3-D shapes of clumps and arbitrary 3-D velocity fields. The method we developed allows us to take into account contributions from density and velocity wind inhomogeneities to the total opacity very precisely. The first comparison with observation shows that 3-D density and velocity wind inhomogeneities have a very strong influence on the resonance line formation, and that they have to be accounted for in order to obtain reliable mass-loss rate determinations.