MAXIMUM MASS INSTABILITY OF NEUTRON-STARS AND WEAK INTERACTION PROCESSES IN DENSE MATTER

We study the stability of equilibrium configurations of neutron stars in the vicinity of maximum allowable mass (mass M congruent-to M(max), central density rho(c) congruent-to rho(c,max)). The effect of weak i nteraction processes on the dynamical properties of perturbed stars is studied. Linear analysis performed for a specific model of dense matt er shows, that due to the slowness of weak interaction processes, the region of configurations stable with respect to infinitesimal radial p erturbations extends beyond rho(c,max). Finite amplitude analysis of s tability is performed using fully relativistic spherically symmetric h ydrodynamical code. We show that for rho(c) close to rho(c,max), confi gurations with rho(c) < rho(c,max) can become unstable with respect to a finite amplitude perturbation. Similarly, those configurations with rho(c) > rho(c,max), which were stable in the linear regime, can be d estabilized, due to non-linear effects, by a small but finite amplitud e perturbation which exceeds some threshold value. In all cases, desta bilized metastable configurations collapse into a black hole.