Neutron stars: A novel equation of state with induced surface tension

TL;DR

This paper introduces a new thermodynamically consistent equation of state with induced surface tension to model neutron star properties, successfully matching observational and collision data constraints.

Contribution

It extends a particle interaction model with surface tension to neutron star matter, providing a causality-preserving, thermodynamically consistent framework for dense matter analysis.

Findings

Mass-radius relations consistent with observational data

Hard core radius of baryons estimated between 0.425 and 0.476 fm

Model aligns with nuclear collision data constraints

Abstract

A novel equation of state with the surface tension induced by particles' interactions was generalized to describe the properties of the neutron stars (NSs). In this equation the interaction between particles occurs via the hard core repulsion by taking into account the proper volumes of particles. Recently, this model was successfully applied to the description of the properties of nuclear and hadron matter created in collisions of nucleons. The new approach is free of causality problems and is fully thermodynamically consistent, which enables us to use it for the investigation of the strongly interacting matter phase-diagram properties in a wide range of temperatures and baryon densities, including NSs. Here, we have calculated the mass-radius relations for a compact star using the Tolmann-Oppenheimer-Volkov (TOV) equation for two sets of parameters that satisfy the existing constraints. Accordingly, we found parameter values that are in good agreement with the same ones obtained from the nuclear-nuclear collision data analysis. The astrophysical constraints suggest that the hard core radius of baryons can vary between 0.425 fm and 0.476 fm.