Rapid emission-line variations in the UV spectrum of the Wolf-Rayet system HD 90657.

Abstract

The authors report IUE observations of the Wolf-Rayet binary system HD 90657 which indicate that a major change in the properties of the W-R wind occurred on time scales of less than 90 minutes. These are very rapid variations when compared to those resulting from atmospheric eclipse effects, which are also observed in this system. The rapid change is attributed to wind instabilities, possibly induced by pulsations of the underlying helium-burning core.