Difference between quark stars and neutron stars in universal relations and their effect on gravitational waves

TL;DR

This paper investigates differences in universal relations between quark stars and neutron stars, focusing on their impact on gravitational wave signals during inspiral, and finds that certain distinguishing effects are undetectable with future detectors.

Contribution

It extends the understanding of universal relations to quark stars and assesses their influence on gravitational wave signals, highlighting the limitations of current detection capabilities.

Findings

Quark stars have smaller radii than neutron stars at low masses.

The relation between tidal deformability and $f$-mode frequency differs for quark and neutron stars.

Tidal dephasing effects are too small to be detected by next-generation gravitational wave detectors.

Abstract

We calculate the $f$-mode frequency and tidal overlap of quark stars using the full general relativity method. We verify the universal relations obtained from conventional neutron stars in the case of quark stars and explore the cases with different values of parameters of the quark star equation of state. Since quark stars have significantly smaller radii compared to neutron stars in the low mass range, the relation between the tidal defomability and $f$-mode frequency times radius is different for neutron stars and quark stars. This difference has an impact on dynamical tide, which is the lowest-order effect we know of that can distinguish quark stars and neutron stars from the gravitational wave during the inspiral phase. We calculate the tidal dephasing caused by this effect in the post-Newtonian method and find that it can not be detected even by the next-generation gravitational wave detectors.