Transition density and pressure in hot neutron stars

TL;DR

This study investigates how transition density and pressure at the crust-core boundary of hot neutron stars depend on temperature, neutrino trapping, and nuclear symmetry energy, revealing complex behaviors influenced by these factors.

Contribution

It provides new insights into the effects of temperature and symmetry energy on the crust-core transition in hot neutron stars using the momentum-dependent MDI interaction.

Findings

Transition density and pressure are higher in neutrino-trapped stars.

Both quantities decrease with increasing temperature and symmetry energy slope.

Critical temperature varies with symmetry energy slope and neutrino trapping.

Abstract

Using the momentum-dependent MDI effective interaction for nucleons, we have studied the transition density and pressure at the boundary between the inner crust and liquid core of hot neutron stars. We find that their values are larger in neutrino-trapped neutron stars than in neutrino-free neutron stars. Furthermore, both are found to decrease with increasing temperature of a neutron star as well as increasing slope parameter of the nuclear symmetry energy, except that the transition pressure in neutrino-trapped neutron stars for the case of small symmetry energy slope parameter first increases and then decreases with increasing temperature. We have also studied the effect of the nuclear symmetry energy on the critical temperature above which the inner crust in a hot neutron star disappears and found that with increasing value of the symmetry energy slope parameter, the critical temperature decreases slightly in neutrino-trapped neutron stars but first decreases and then increases in neutrino-free neutron stars.