Rotation and deformation of strangeon stars in the Lennard-Jones model

TL;DR

This paper models strangeon stars using the Lennard-Jones potential to explore their deformation, rotation, and universal properties, providing insights for astrophysical observations and constraints.

Contribution

It introduces a novel application of the Lennard-Jones model to describe the equation of state of strangeon stars, including their deformation and universal relations.

Findings

Universal relations between moments of inertia, tidal deformabilities, and quadrupole moments are established.

Finite surface density corrections are significant in perturbative approaches.

The model's predictions can be tested with future gravitational wave and electromagnetic observations.

Abstract

The strong interactions at low energy scales determine the state of the supranuclear matter in the pulsar-like compact objects. It is proposed that the bulk strong matter could be composed of strangeons, which are quark clusters with a nearly equal number of three light-flavor quarks. In this work, to characterize the strong-repulsive interactions at short distances and the non-relativistic nature of the strangeons, the Lennard-Jones model is used to describe the equation of state (EoS) of strangeon stars (SSs). We investigate the static, the slowly rotating, and the tidally deformed SSs in detail. The corrections resulted from the finite surface densities are considered crucially in the perturbative approaches. We also study the universal relations between the moments of inertia, the tidal deformabilities, and the quadrupole moments. Those results are ready to be used for various purposes in astrophysics, and possible constraints from contemporary observations on the parameter space of the Lennard-Jones model are discussed. Future observations of the pulsars' radio signals, the X-ray emissions from the hot spots on the surface of the stars, and the gravitational waves (GWs) from binary mergers can give tighter constraints or even verify or falsify the existence of SSs.