# Study of the core-crust transition in neutron stars with finite-range interactions: the dynamical method

## TL;DR

This paper investigates the core-crust transition in neutron stars using finite-range nuclear forces and the dynamical method, highlighting differences from the thermodynamical approach and implications for neutron star properties.

## Contribution

It introduces a detailed analysis of the core-crust transition using the dynamical method with finite-range interactions, emphasizing finite-size effects and comparing with thermodynamical results.

## Key findings

- Dynamical method yields different transition densities and pressures than thermodynamical method.
- Finite-range forces influence the core-crust transition properties.
- Transition point significantly affects neutron star crust mass and moment of inertia.

## Abstract

The properties of the core-crust transition in neutron stars are investigated using effective nuclear forces of finite-range. Special attention is paid to the so-called dynamical method for locating the transition point, which, apart from the stability of the uniform nuclear matter against clusterization, also considers contributions due to finite-size effects. In particular, contributions to the transition density and pressure from the direct and exchange energies are carefully analyzed. To this end, finite-range forces of Gogny, Modified Gogny Interaction (MDI) and Simple Effective Interaction (SEI) types are used in the numerical applications. The results from the dynamical approach are compared with those from the popular thermodynamical method that neglects the surface and Coulomb effects in the stability condition. The dependence of the core-crust transition on the stiffness of the symmetry energy of the finite-range models is also addressed. Finally, we analyze the impact of the transition point on the mass, thickness and fraction of the moment of inertia of the neutron star crust. Prominent differences in these crustal properties of the star are found between using the transition point obtained with the dynamical method or the thermodynamical method. It is concluded that the core-crust transition needs to be ascertained as precisely as possible in order to have realistic estimates of the observed phenomena where the crust plays a significant role.