Structure and Cooling of Neutron and Hybrid Stars

TL;DR

This paper explores the structure and cooling mechanisms of neutron and hybrid stars, emphasizing the role of exotic particles, quark cores, and rotation in determining their observable properties and internal composition.

Contribution

It introduces model approaches to calculate neutron star properties incorporating baryons and quarks across various temperatures and densities, linking astrophysical observations with heavy-ion collision data.

Findings

Exotic particles and quark cores significantly affect star mass and radius.

Cooling curves are sensitive to the star's internal composition.

Rotation can drastically alter particle composition within the star.

Abstract

The study of neutron stars is a topic of central interest in the investigation of the properties of strongly compressed hadronic matter. Whereas in heavy-ion collisions the fireball, created in the collision zone, contains very hot matter, with varying density depending on the beam energy, neutron stars largely sample the region of cold and dense matter with the exception of the very short time period of the existence of the proto-neutron star. Therefore, neutron star physics, in addition to its general importance in astrophysics, is a crucial complement to heavy-ion physics in the study of strongly interacting matter. In the following, model approaches will be introduced to calculate properties of neutron stars that incorporate baryons and quarks. These approaches are also able to describe the state of matter over a wide range of temperatures and densities, which is essential if one wants to connect and correlate star observables and results from heavy-ion collisions. The effect of exotic particles and quark cores on neutron star properties will be considered. In addition to the gross properties of the stars like their masses and radii their expected inner composition is quite sensitive to the models used. The effect of the composition can be studied through the analysis of the cooling curve of the star. In addition, we consider the effect of rotation, as in this case the particle composition of the star can be modified quite drastically.