On Wolf-Rayet stars, black holes and co-rotating binary systems.

The problem of black hole formation in a co-rotating binary system is analyzed. The Miller and De Felice critical value of a/m and the co-rotation hypothesis, are used to find critical orbital periods in a Wolf-Rayet system just prior to the collapse of the more evolved star. These critical periods are compared with observational data to find WR binary systems that may produce black holes in the future.