On the Speed of Sound in Hyperonic Stars

TL;DR

This paper investigates the speed of sound in hyperonic stars, demonstrating that the equation of state with hyperons aligns with recent model-independent constraints, allowing for hyperons or quark matter in neutron star cores.

Contribution

It applies the quark-meson coupling model to show hyperons can exist in dense matter consistent with recent constraints, expanding understanding of neutron star composition.

Findings

Equation of state with hyperons matches recent constraints

Hyperons are compatible with the presence of quark matter in neutron stars

Constraints do not exclude hyperons in dense stellar cores

Abstract

We build upon the remarkable, model independent constraints on the equation of state of dense baryonic matter established recently by Annala et al. [1]. Using the quark-meson coupling model, an approach to nuclear structure based upon the self-consistent adjustment of hadron structure to the local meson fields, we show that, once hyperons are allowed to appear in dense matter in \b{eta}-equilibrium, the equation of state is consistent with those constraints. As a result, while one cannot rule out the occurence of quark matter in the cores of massive neutron stars, the available constraints are also compatible with the presence of hyperons.