Tidal deformability of strange stars and the GW170817 event

TL;DR

This study models strange stars with color-flavor-locked quark matter to analyze their tidal deformability and compare it with GW170817 data, constraining model parameters and supporting the viability of strange stars in binary mergers.

Contribution

It introduces a detailed CFL phase model with gluon effects and constrains the vector coupling parameter using multiple astrophysical observations.

Findings

Allowed G_V parameter windows compatible with observations.

Strong correlation between tidal deformability and G_V.

Strange stars remain plausible in binary mergers.

Abstract

In this work we consider strange stars formed by quark matter in the color-flavor-locked (CFL) phase of color superconductivity. The CFL phase is described by a Nambu-Jona-Lasinio model with four-fermion vector and diquark interaction channels. The effect of the color superconducting medium on the gluons are incorporated into the model by including the gluon self-energy in the thermodynamic potential. We construct parametrizations of the model by varying the vector coupling $G_V$ and comparing the results to the data on tidal deformability from the GW170817 event, the observational data on maximum masses from massive pulsars such as the MSP J0740+6620, and the mass/radius fits to NICER data for PSR J003+0451. Our results points out to windows for the $G_V$ parameter space of the model, with and without gluon effects included, that are compatible with all these astrophysical constraints, namely, $0.21<G_V/G_S<0.4$, and $0.02<G_V/G_S<0.1$, respectively. We also observe a strong correlation between the tidal deformabilites of the GW170817 event and $G_V$. Our results indicate that strange stars cannot be ruled out in collisions of compact binaries from the structural point of view.