O-star mass-loss rates (L. B. Lucy)

Vol. 542
In section 8. Stellar atmospheres

O-star mass-loss rates at low metallicity

by L. B. Lucy, A&A 542, A18

Recent wind determinations in low-metallicity OB stars in extragalactic systems have been seriously at odds with model predictions for stellar winds. Some of the discrepency is purely observational, such as the neglect of the systematic effect of wind clumping and the reduced volume-filling factors for the complex winds. However, another possibility is that there is an acceleration mechanism at work that is formally similar to radiative driving but has different metallicity and density dependences. The author seeks to place constraints on these mechanisms.