Core-crust transition in neutron stars: Predictivity of density developments

Abstract

The possibility to draw links between the isospin properties of nuclei and the structure of compact stars is a stimulating perspective. In order to pursue this objective on a sound basis, the correlations from which such links can be deduced have to be carefully checked against model dependence. Using a variety of nuclear effective models and a microscopic approach, we study the relation between the predictions of a given model and those of a Taylor density development of the corresponding equation of state: this establishes to what extent a limited set of phenomenological constraints can determine the core-crust transition properties. From a correlation analysis, we show that (a) the transition density ${\ensuremath{\rho}}_{t}$ is mainly correlated with the symmetry energy slope $L$, (b) the proton fraction ${Y}_{p,t}$ with the symmetry energy and symmetry energy slope $(J,L)$ defined at saturation density, or, even better, with the same quantities defined at $\ensuremath{\rho}=0.1$ fm${}^{\ensuremath{-}3}$, and (c) the transition pressure ${P}_{t}$ with the symmetry energy slope and curvature $(L,{K}_{\mathrm{sym}})$ defined at $\ensuremath{\rho}=0.1$ fm${}^{\ensuremath{-}3}$.