Inner crust of neutron stars with mass-fitted Skyrme functionals

TL;DR

This paper calculates the equation of state and composition of neutron star inner crusts using Skyrme functionals, revealing consistent proton numbers across different models and solving TOV equations for mass distribution.

Contribution

It introduces a comprehensive analysis of the inner crust of neutron stars using mass-fitted Skyrme functionals and the TETFSI method, providing new insights into crust composition and structure.

Findings

Proton number per Wigner-Seitz cell is consistently 40 across models.

Qualitative similarity in results for different Skyrme functionals.

Mass distribution within the crust is obtained by solving TOV equations.

Abstract

The equation of state and composition of the inner crust of neutron stars at zero temperature are calculated, using the T = 0 version of the TETFSI (temperature-dependent extended Thomas-Fermi plus Strutinsky integral) method, for each of a family of three functionals based on Skyrme-type forces BSk19, BSk20 and BSk21, which are characterized by different degrees of symmetry-energy stiffness, and also for the SLy4 functional. We also solve the Tolman-Oppenheimer-Volkoff equations to calculate the distribution of mass within the inner crust. Qualitatively similar results are found for all four functionals, and in particular the number of protons per Wigner-Seitz cell is in all cases equal to 40 throughout the inner crust.