Neutron star deformability with hyperonization in density-dependent relativistic mean-field models

TL;DR

This paper investigates how hyperons influence neutron star tidal deformability within density-dependent relativistic mean-field models, highlighting their significant impact on the interpretation of gravitational wave data and the nuclear equation of state.

Contribution

It introduces hyperons into the relativistic mean-field framework to study their effect on neutron star deformability and explores how hyperon onset density affects gravitational wave inferences.

Findings

Hyperons significantly affect neutron star deformability.

Lower hyperon onset density alters tidal deformability measurements.

Future data can distinguish hyperon effects from symmetry energy contributions.

Abstract

Neutron star tidal deformability extracted from gravitational wave data provides a novel probe to the interior neutron star structures and the associated nuclear equation of state (EOS). Instead of the popular composition of nucleons and leptons in neutron stars, we include hyperons and examine the role of hyperons in the tidal deformability and its impact on the symmetry energy in a relativistic mean-field approach with the density-dependent parametrizations. The hyperons are found to have significant impact on the deformability, correlated sensitively with the onset density and fraction of hyperons in neutron star matter. Moderately lower onset density of hyperons can yield considerable modification to the tidal deformability and shift its inference on the nuclear EOS. The future measurements of the tidal deformability at multi-fiducial star masses are anticipated to lift the degeneracy between the contributions from the hyperon component and symmetry energy.