Stellar Superfluids

TL;DR

This paper reviews how superfluidity in neutron stars influences their thermal evolution and observational signatures, providing insights into dense matter physics through neutron star cooling and pulsar data.

Contribution

It synthesizes observational evidence and theoretical models to advance understanding of superfluidity's role in neutron star behavior and properties.

Findings

Cooling neutron stars help constrain nucleon pairing models.

Pulsar observations support widespread superfluidity in neutron stars.

Thermal evolution data restrict superfluid properties at high densities.

Abstract

Neutron stars provide a fertile environment for exploring superfluidity under extreme conditions. It is not surprising that Cooper pairing occurs in dense matter since nucleon pairing is observed in nuclei as energy differences between even-even and odd-even nuclei. Since superfluids and superconductors in neutron stars profoundly affect neutrino emissivities and specific heats, their presence can be observed in the thermal evolution of neutron stars. An ever-growing number of cooling neutron stars, now amounting to 13 thermal sources, and several additional objects from which upper limits to temperatures can be ascertained, can now be used to discriminate among theoretical scenarios and even to dramatically restrict properties of nucleon pairing at high densities. In addition, observations of pulsars, including their spin-downs and glitch histories, additionally support the conjecture that superfluidity and superconductivity are ubiquitous within, and important to our understanding of, neutron stars.