Angular momentum loss from contact binary systems.

The effect of angular momentum loss on zero-age main sequence contact binary systems constructed according to the Lucy model is investigated. It is found that the separation of the mass centres decreases, the mass ratio decreases, and the system adopts a dumb-bell configuration. If the system reaches a configuration in which it fills its outer closed common equipotential surface it is unstable to mass loss with the local angular momentum through the outer Lagrange point.