Strangeness in Compact Stars

TL;DR

This paper explores how strange hadrons, especially hyperons, affect the structure, evolution, and observable properties of compact stars and supernovae, highlighting their significant astrophysical implications.

Contribution

It provides a comprehensive analysis of hyperons' role in neutron star physics and supernovae, integrating astrophysical observations with heavy-ion collision constraints.

Findings

Hyperons appear around twice nuclear saturation density in neutron star cores.

Their presence influences the mass-radius relation and maximum mass of neutron stars.

Constraints from heavy-ion collisions limit the maximum neutron star mass.

Abstract

We discuss the impact of strange hadrons, in particular hyperons, on the gross features of compact stars and on core-collapse supernovae. Hyperons are likely to be the first exotic species which appears around twice normal nuclear matter density in the core of neutron stars. Their presence largely influences the mass-radius relation of compact stars, the maximum mass, the cooling of neutron stars, the stability with regard to the emission of gravitational waves from rotation-powered neutron stars and the possible early onset of the QCD phase transition in core-collapse supernovae. We outline also the constraints from subthreshold kaon production in heavy-ion collisions for the maximum possible mass of neutron stars.