Half-vortex states in the rotating outer core of neutron stars

TL;DR

This paper investigates the behavior of half-vortex states in the rotating outer core of neutron stars using a generalized hydrodynamic model, revealing how proton flux tubes influence neutron superfluid dynamics.

Contribution

It introduces a coupled hydrodynamic model incorporating entrainment and nucleon interactions to analyze vortex states in neutron star cores.

Findings

Proton flux tubes induce hydrodynamic perturbations in neutron superfluid.

Neutron superfluid structure remains stable across varying rotation rates and magnetic fields.

The model provides insights into vortex interactions in neutron star cores.

Abstract

We probe the superfluid-superconductor dynamics of the rotating outer core of neutron stars through half-vortex states. By means of a generalized hydrodynamic model, where proton and neutron fluids are coupled by both dynamic entrainment and Skyrme SLy4 nucleon-nucleon interactions, we analyze single flux tubes in the proton-superconductor component of the system that thread proton vortices located faraway from neutron vortices. It is shown how they give rise to hydrodynamic perturbations in the coexisting neutron superfluid, and its structure remains unaltered for varying rotation rates and magnetic fields within ranges of observational values.