The Evolution of Massive Stars: The Production of “Single” WR Stars

Abstract

In this paper we summarize the basic observational properties of WR stars, and the current status of the evolution of massive stars, giving particular emphasis to those physical mechanisms (mass loss, overshooting, turbulent diffusion…) that may lead O type stars to the WR stage. We consider only those scenarios for WR formation and evolution that have been developed during the last few years and that appear to be sufficiently substanciated by observational and theoretical arguments. Finally, the theoretical results are compared with the observations, pointing out several still unsettled aspects of the problem.

Wolf-Rayet Phenomena

“…Details of the work in this very active field are provided later in this Symposium (Chiosi 1982). The mass and composition of a stel lar model, and their rates of change, can lead, in principle, to pre dicted luminosities and temperatures of stars.…”