Superfluid Heat Conduction and the Cooling of Magnetized Neutron Stars

TL;DR

This paper introduces a new heat conduction mechanism in magnetized neutron star crusts involving superfluid phonons, which can significantly affect thermal evolution and surface temperature anisotropy.

Contribution

It identifies superfluid phonons as a dominant heat conduction mode in magnetized neutron stars, especially at high magnetic fields, impacting cooling behavior.

Findings

Superfluid phonons can dominate transverse heat conduction at B > 10^{13} G.

Superfluid phonon conductivity exceeds lattice phonons at certain densities and temperatures.

This mechanism can alter observable cooling curves of neutron stars.

Abstract

We report on a new mechanism for heat conduction in the neutron star crust. We find that collective modes of superfluid neutron matter, called superfluid phonons (sPhs), can influence heat conduction in magnetized neutron stars. They can dominate the heat conduction transverse to magnetic field when the magnetic field $B \gsim 10^{13}$ G. At density $\rho \simeq 10^{12}-10^{14} $ g/cm$^3$ the conductivity due to sPhs is significantly larger than that due to lattice phonons and is comparable to electron conductivity when temperature $\simeq 10^8$ K. This new mode of heat conduction can limit the surface anisotropy in highly magnetized neutron stars. Cooling curves of magnetized neutron stars with and without superfluid heat conduction could show observationally discernible differences.