New quasi-universal relations for static and rapid rotating neutron stars

TL;DR

This paper introduces new quasi-universal relations for neutron stars that connect gravitational redshift and binding energy across static and rotating cases, aiding in constraining their unobservable properties.

Contribution

It proposes novel quasi-universal relations involving gravitational redshift and binding energy for various neutron star rotation states, based on multiple equations of state.

Findings

Relations hold across 11 EOSs for static and rotating neutron stars.

Potential to estimate unobservable properties of neutron stars.

Enhances understanding of neutron star physics with new universal relations.

Abstract

In the last few decades, lots of universal relations between different global physical quantities of neutron stars have been proposed to constrain the unobservable or hard to be observed properties of neutron stars. But few of them are related to the gravitational redshift or the gravitational binding energy, especially for the fast rotating neutron stars. Here we will focus on the universal relations related to these two quantities. Based on 11 equations of state (EOSs) from the predictions of microscopic nuclear many-body theories for normal or hybrid neutron stars, we proposed a set of new quasi-universal relations under three rotating cases: static, general rotating and Keplerian rotating. These new quasi-universal relations provide a potential way to constrain or estimate the unobservable or hard to be observed properties of neutron stars.