Rotating Quark Stars in General Relativity

Enping Zhou,Renxin Xu,Antonios Tsokaros,Luciano Rezzolla,Kōji Uryū

doi:10.3390/universe4030048

Abstract

We have built quasi-equilibrium models for uniformly rotating quark stars in general relativity. The conformal flatness approximation is employed and the Compact Object CALculator (cocal) code is extended to treat rotating stars with surface density discontinuity. In addition to the widely used MIT bag model, we have considered a strangeon star equation of state (EoS), suggested by Lai and Xu, that is based on quark clustering and results in a stiff EoS. We have investigated the maximum mass of uniformly rotating axisymmetric quark stars. We have also built triaxially deformed solutions for extremely fast rotating quark stars and studied the possible gravitational wave emission from such configurations.

Highlights

The gravitational-wave (GW) event GW170817 and the associated electromagnetic emission observations [1,2] from a binary neutron star (BNS) merger has announced the birth of a multimessenger observation era
The maximum mass of a static spherical compact star and an axisymmetric rotating compact star depends on the equation of state (EoS) and is closely related to the post-merger phase of a BNS merger
It has been found that the maximum mass of uniformly rotating neutron stars (NSs), compared with the TOV maximum mass, depends very weakly on EoSs [15]

Summary

Introduction

The gravitational-wave (GW) event GW170817 and the associated electromagnetic emission observations [1,2] from a binary neutron star (BNS) merger has announced the birth of a multimessenger observation era. Following the first study on the equilibrium models of uniformly rotating, incompressible fluid stars in a Newtonian gravity scheme [12], various works have been done with more realistic EoSs and general relativity [13,14]. Among those studies, quasi-universal relationship has been found for both uniformly rotating and differentially rotating NSs [15,16,17,18,19,20]. We have built a uniformly rotating axisymmetric and triaxial sequence for quark stars

Maximum Mass of Axisymmetric Rotating Quark Stars

Triaxial Rotating Quark Stars

Discussion