Effects of the Symmetry Energy and its Slope on Neutron Star Properties

TL;DR

This study investigates how the symmetry energy and its slope influence key neutron star properties, revealing strong correlations with radius and direct URCA mass, while maximum mass remains largely unaffected.

Contribution

The paper introduces an analysis of the effects of symmetry energy and its slope on neutron star properties using four relativistic models, highlighting their impact on radius and URCA threshold.

Findings

Radius of 1.4 solar mass neutron stars is strongly correlated with symmetry energy and its slope.

Maximum neutron star mass is nearly independent of symmetry energy variations.

A theoretical limit on radius growth is identified when the slope exceeds certain values.

Abstract

In this work we study the influence of the symmetry energy and its slope on three major properties of neutron stars: the maximum mass, the radii of the canonical 1.4$M_\odot$ and the minimum mass that enables the direct URCA effect. We utilize four parametrizations of the relativistic quantum hadrodynamics and vary the symmetry energy within accepted values. We see that although the maximum mass is almost independent of it, the radius of the canonical $1.4M_\odot$ and the mass that enables the direct URCA effect is strongly correlated with the symmetry energy and its slope. Also, since we expect that the radius grows with the slope, a theoretical limit arises when we increase this quantity above certain values.