The Vlasov formalism for extended relativistic mean field models: the crust-core transition and the stellar matter equation of state

TL;DR

This paper extends the Vlasov formalism to relativistic mean-field models with nonlinear terms to analyze the crust-core transition in neutron stars, examining how coupling terms influence star properties and comparing model predictions with observational constraints.

Contribution

It introduces an extended Vlasov formalism for nonlinear relativistic mean-field models and investigates the impact of specific coupling terms on neutron star crust-core transition and macroscopic properties.

Findings

Crust-core transition density and pressure are affected by nonlinear coupling terms.

Predicted neutron star radius is approximately 13.6 km for a 1.4 solar mass star.

Inclusion of pasta phases influences the star radius and crust thickness.

Abstract

The Vlasov formalism is extended to relativistic mean-field hadron models with non-linear terms up to fourth order and applied to the calculation of the crust-core transition density. The effect of the nonlinear $\omega\rho$ and $\sigma\rho$ coupling terms on the crust-core transition density and pressure, and on the macroscopic properties of some families of hadronic stars is investigated. For that purpose, six families of relativistic mean field models are considered. Within each family, the members differ in the symmetry energy behavior. For all the models, the dynamical spinodals are calculated, and the crust-core transition density and pressure, and the neutron star mass-radius relations are obtained. The effect on the star radius of the inclusion of a pasta calculation in the inner crust is discussed. The set of six models that best satisfy terrestrial and observational constraints predicts a radius of 13.6$\pm$0.3 km and a crust thickness of $1.36\pm 0.06$km for a 1.4 $M_\odot$ star.