Interplay between the symmetry energy and the strangeness content of neutron stars

TL;DR

This paper investigates how the symmetry energy and strangeness content influence neutron star properties, emphasizing the need for better high-density nuclear matter data to understand their effects and correlations.

Contribution

It explores the interplay between symmetry energy and hyperon content in neutron stars using relativistic mean field models, highlighting the importance of high-density EoS data.

Findings

Star properties are similarly affected by symmetry energy and hyperon content.

A linear correlation exists between star radius and strangeness content at fixed mass.

Uncertainty in high-density EoS limits definitive conclusions about exotic matter in pulsars.

Abstract

The effect of the density dependence of the nucleonic equation of state and the hyperon meson couplings on the star properties, including strangeness content, mass and radius, are studied within a relativistic mean field formalism. It is shown that there is still lacking information on the nucleonic equation of state at supra-saturation densities and on the hyperon interactions in nuclear matter that will allow a clear answer to the question whether the mass of the pulsar J1614-2230 could rule out exotic degrees of freedom from the interior of compact stars. We show that some star properties are affected in a similar way by the density dependence of the symmetry energy and the hyperon content of the star. To disentangle these two effects it is essential to have a good knowledge of the equation of state at supra-saturation densities. A linear correlation between the radius and the strangeness content of a star with a fixed mass is obtained.