Crust-core transition of a neutron star: effects of the symmetry energy and temperature under strong magnetic fields

Abstract

We study the simultaneous effects of the symmetry energy and temperature on the crust-core transition of a magnetar. The dynamical and the thermodynamical spinodals are used to calculate the transition region within a relativistic mean-field approach for the equation of state. Quantizing magnetic fields with intensities in the range of $ 2\times 10^{15}<B<5\times 10 ^{16}$G are considered. Under these strong magnetic fields, the crust extension is very sensitive to the density dependence of the symmetry energy, and the properties that depend on the crust thickness could set a constraint on the equation of state. It is shown that the effect on the extension of the crust-core transition is washed out for temperatures above $10^{9}$ K. However, for temperatures below that value, a noticeable effect exists that grows as the temperature decreases and which should be taken into account when the evolution of magnetars is studied.