Convective instability in proto-neutron stars

The linear hydrodynamic stability of proto-neutron stars (PNSs) is considered, taking into account dissipative processes such as neutrino transport and viscosity. We obtain the general instability criteria, which differ essentially from the well-known Ledoux criterion used in previous studies. We apply the criteria to evolutive models of PNSs that, in general, can be subject to the various known regimes such as neutron fingers and convective instabilities. Our results indicate that the fingers instability arises in a more extended region of the stellar volume and lasts a longer time than expected.