Vortex distribution in neutron stars: gravitational effects

TL;DR

This paper investigates how gravitational effects, including frame dragging, alter vortex distribution in neutron star superfluids, impacting models of neutron star rotation and observable phenomena.

Contribution

It demonstrates that gravity and inertial frame dragging significantly modify vortex density and shape in neutron star superfluids, a novel insight for neutron star physics.

Findings

Frame dragging reduces vortex density by about 15%.

Gravitational effects alter vortex distribution and shape.

Implications for neutron star rotation models.

Abstract

Neutron stars are supposed to be mainly formed by a neutron superfluid. The angular momentum is given by the vortex array within the fluid, and a good account of the observable effects is determined by its coupling with the crust. In this article we show that the gravitational field introduces important modifications in the vortex distribution and shape. The inertial frame dragging on the quantum fluid produces a decrease in the vortex density, which for realistic models is in the order of 15%. This effect is relevant for neutron star rotation models and can provide a good framework for checking the quantum effect of the frame dragging.