Strange mode instabilities and mass loss in evolved massive primordial stars

A linear stability analysis of models for evolved primordial stars with masses between 150 and 250M(circle dot) is presented. Strange mode instabilities with growth rates in the dynamical range are identified for stellar models with effective temperatures below log T-eff = 4.5. For selected models, the final fate of the instabilities is determined by numerical simulation of their evolution into the non-linear regime. As a result, the instabilities lead to finite amplitude pulsations. Associated with them are acoustic energy fluxes capable of driving stellar winds with mass-loss rates in the range between 7.7 x 10(-7) and 3.5 x 10(-4) M-circle dot yr(-1).