Validity of clumping approximations for mass-loss rates determination

TL;DR

This paper investigates how different assumptions about wind clumping in hot stars affect the theoretical predictions of their mass-loss rates, highlighting the importance of clumping properties below the critical point.

Contribution

It analyzes the impact of various clumping factors on mass-loss rate predictions, emphasizing the significance of clumping below the critical point in stellar wind models.

Findings

Clumping influences mass-loss rate calculations.

Different clumping factors lead to varied spectral fits.

Clumping below the critical point significantly affects predictions.

Abstract

Clumping in stellar winds of hot stars is a possible consequence of radiative-acoustic instability appearing in solutions of radiative-hydrodynamical equations. However, clumping is usually included to stellar atmosphere modeling and radiative transfer calculations in a highly approximate way via a global free parameter called the clumping factor. Using different values of clumping factors many researchers succeeded to fit the observed spectra better and to correct empirical mass loss rates. This usually leads to a conclusion that the stellar wind is clumped. To understand how clumping may influence theoretical predictions of mass-loss rates, different clumping properties have to be taken into account. If clumping appears already below the critical point, the mass-loss rates is changed.