ABSTRACT
Most of the analysis of stellar evolution used nonrotating models. This choice was made for the sake of convenience. Although we know the equa tions, exact solutions are very difficult to acheive. However we do know that all astrophysical objects rotate, and the rotation undoubtedly affects the evolutionary tracks of these objects to some extent. This means that the consequences deduced from the analysis of nonrotating objects only suit objects with a low rotation velocity. Here we consider the effects of rotation as small perturbations on the zero order approximation, the nonrotating model. The earliest introduction of rotation effects into stellar evolution cal culations was actually through calculating rotation-induced perturbations on nonrotating calculated models.
