Constraints on interquark interaction parameters with GW170817 in a binary strange star scenario

TL;DR

This paper uses GW170817 gravitational wave data to constrain parameters of quark star models, especially the effective bag constant, and discusses implications for the maximum mass and pairing gap in quark matter.

Contribution

It provides the first detailed analysis of how GW170817 constrains interquark interaction parameters in binary strange star scenarios.

Findings

Tidal deformability is mainly influenced by the effective bag constant.

Current measurements limit the maximum mass of quark stars to about 2.18-2.32 solar masses.

Constraints on the pairing gap parameter in quark matter are derived from combined gravitational wave and pulsar data.

Abstract

The LIGO/VIRGO detection of the gravitational waves from a binary merger system, GW170817, has put a clean and strong constraint on the tidal deformability of the merging objects. From this constraint, deep insights can be obtained in compact star equation of states, which has been one of the most puzzling problems for nuclear physicists and astrophysicists. Employing one of the most widely-used quark star EOS model, we characterize the star properties by the strange quark mass ($m_s$), an effective bag constant ($B_{\rm eff}$), the perturbative QCD correction ($a_4$), as well as the gap parameter ($\Delta$) when considering quark pairing, and investigate the dependences of the tidal deformablity on them. We find that the tidal deformability is dominated by $B_{\rm eff}$, and insensitive to $m_s$, $a_4$. We discuss the correlation between the tidal deformability and the maximum mass ($M_\mathrm{TOV}$) of a static quark star, which allows the model possibility to rule out the existence of quark stars with future gravitational wave observations and mass measurements. The current tidal deformability measurement implies $M_\mathrm{TOV} \le2.18\,M_\odot$ ($2.32\,M_\odot$ when pairing is considered) for quark stars. Combining with two-solar-mass pulsar observations, we also make constraints on the poorly known gap parameter $\Delta$ for color-flavor-locked quark matter.