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

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 rho(t) is mainly correlated with the symmetry energy slope L, (b) the proton fraction Y-p,Y-t with the symmetry energy and symmetry energy slope (J, L) defined at saturation density, or, even better, with the same quantities defined at rho = 0.1 fm(-3), and (c) the transition pressure P-t with the symmetry energy slope and curvature (L, K-sym) defined at rho = 0.1 fm(-3).