Metallicity Dependent Wolf-Rayet Winds

Abstract

Observational and theoretical evidence in support of metallicity dependent winds for Wolf-Rayet stars is considered. Well known differences in Wolf-Rayet subtype distributions in the Milky Way, LMC and SMC may be attributed to the sensitivity of subtypes to wind density. Implications for Wolf-Rayet stars at low metallicity include a hardening of ionizing flux distributions, an increased WR population due to reduced optical line fluxes, plus support for the role of single WR stars as Gamma Ray Burst progenitors.