Massive Close Binaries

The evolution of massive stars in general, massive close binaries in par­ ticular depend on processes where, despite many efforts, the physics are stiU uncertain. Here we discuss the effects of stellar wind as function of metallicity during different evolutionary phases and the effects of rota­ tion and we highlight the importance for population (number) synthesis. Models are proposed for the X-ray binaries with a black hole component. We then present an overall scheme for a massive star PNS code. This code, in combination with an appropriate set of single star and close binary evolutionary computations predicts the O-type star and Wolf­ Rayet star population, the population of double compact star binaries and the supernova rates, in regions where star formation is continuous in time.