Stability of a collapsed star in bimetric general relativity. II

According to the bimetric general relativity theory, after a star has undergone gravitational collapse, it fills its Schwarzschild sphere and reaches hydrostatic equilibrium. The question investigated is whether the equilibrium is stable. This question was considered in an earlier paper, where it was assumed that the star had zero pressure. In the present work a more realistic equation of state is assumed. It is found that for the equilibrium state comsidered, the assumed small perturbations have one unstable mode. However, the time constant of the instability is of the order of the age of the universe. Since there exists a second nonsingular equilibrium state, it may be that the instability is due to the possibility of a transition to this state. 5 refs