Abstract
The considerable radiative pressure of massive hot stars is a very efficient engine for the ejection of stellar winds. In addition, hot stars are often also fast rotators. In this case, their flattened photosphere results in overheated polar caps through the Von Zeipel effect, and a low effective gravity at the equator. Mass loss occurs from both the poles (fast stellar wind) and the equator (slower wind). The geometry of the envelopes of fast rotating stars is therefore often assumed to be formed by a hot polar wind and a disk around the stellar equator. As most massive stars are members of binary or multiple systems, stellar interactions also play an fundamental role. In this article, we report recent results from long-baseline interferometry focused on two hot stars with winds detected by interferometry: Achernar and η Carinae.
