Magnetic-type Love number differentiating quark stars from neutron stars

TL;DR

This paper proposes that the magnetic-type Love number can effectively distinguish quark stars from neutron stars, especially when their radii and masses overlap, with implications for gravitational wave detection.

Contribution

It introduces the magnetic-type Love number as a new, robust indicator to differentiate quark stars from neutron stars, surpassing electric-type Love number limitations.

Findings

Magnetic Love number effectively differentiates QSs from NSs.

Electric Love number is insufficient for overlapping mass-radius cases.

Gravitational wave signals can detect differences between QSs and NSs.

Abstract

The quark star (QS) is a hypothetical and yet undiscovered stellar object, and its existence would mark a paradigm shift in research on nuclear and quark matter. Although compactness is a well-known signature for distinguishing between two branches of QSs and neutron stars (NSs), some QSs can overlap with NSs in the radius-mass plane. To manifest their evident differences, we investigate the tidal properties of QSs and NSs. We then find that the magnetic-type Love number is a robust indicator for differentiating between QSs and NSs, whereas the electric-type one is insufficient when QSs and NSs have similar masses and radii. Finally, we show that gravitational waves from binary star mergers can be sensitive to differences between QSs and NSs to the detectable level.