Cooling curves for neutron stars with hadronic matter and quark matter

TL;DR

This paper investigates the thermal evolution of neutron stars with hadronic and quark matter, highlighting the effects of neutrino emission and superfluidity on their cooling behavior.

Contribution

It introduces models of neutron star cooling that incorporate mixed phases and superfluidity, showing their impact on cooling rates and observational consistency.

Findings

Superfluidity significantly slows down neutron star cooling.

Cooling curves are insensitive to the details of phase mixing and pairing.

Direct Urca process dominates early-stage neutrino emission.

Abstract

The thermal evolution of isothermal neutron stars is studied with matter both in the hadronic phase as well as in the mixed phase of hadronic matter and strange quark matter. In our models, the dominant early-stage cooling process is neutrino emission via the direct Urca process. As a consequence, the cooling curves fall too fast compared to observations. However, when superfluidity is included, the cooling of the neutron stars is significantly slowed down. Furthermore, we find that the cooling curves are not very sensitive to the precise details of the mixing between the hadronic phase and the quark phase and also of the pairing that leads to superfluidity.