A comment on some oscillatory models of adiabatic stars

Three different oscillatory models of adiabatic stars are reinvestigated. These are the homogenous model, the inverse square model and the Roche model. The ratio between the amplitude of the oscillations and the distance from the center is developed in a power series. For physical conclusions to be drawn, it turns out to be crucial if the power series is divergent or convergent. Mathematical arguments are given which show that the power series are really divergent for all three models.