Neutrino diffusion and mass ejection in protoneutron stars

We discuss the mass ejection mechanism induced by diffusion of neutrino during the early stage of the protoneutron star cooling. A dynamical calculation is employed in order to determine the amount of matter ejected and the remnant compact object mass. An equation of state considering hadronic and quark phases for the stellar dense matter was used to solve the whole time evolution of the system during the cooling phase. The initial neutrino population was obtained by considering beta equilibrium in the dense stellar matter with confined neutrinos, in the very early period of the deleptonic stage of the nascent pulsar. For specified initial configurations of the protoneutron star, we solve numerically the set of equations of motion together with neutrino diffusion through the dense stellar medium.

Figure 1

Time evolution of the outer shell radii for 1.2, 1.4, and $1.6M_{\odot }$ protoneutron star, when we consider $P_{\nu }=0$ and ${\kappa }_{\nu }\ne 0$.

Figure 2

Same as Fig. 1, but now considering $P_{\nu }\ne 0$ and ${\kappa }_{\nu }\ne 0$.

Figure 3

On this detail of the outer shell bounce, we may better observe the evolutive curve of the inner shell along the reversion of the outer shell movement on three different initial masses.