Anisotropic hybrid stars: Interplay of superconductivity and magnetic field leading to gravitational waves

TL;DR

This paper explores how superconductivity and magnetic fields influence hybrid star structure and gravitational wave signals, proposing new models to understand their observable signatures.

Contribution

It introduces a phenomenological anisotropy model for hybrid stars incorporating superconductivity and magnetic fields, linking internal physics to gravitational wave observations.

Findings

Superconductivity and magnetic fields induce pressure anisotropy in hybrid stars.

The model predicts mass enhancements and gravitational wave signatures.

Anisotropy may help constrain the internal physics of neutron/hybrid stars.

Abstract

Neutron stars, at their cores, are highly dense and, thus, are expected to have a number of exotic processes. This includes a possible phase transition to deconfined quark matter at the core, leading to a hybrid star. The quark matter is expected to additionally be color superconducting. The physics of superconductivity plays an important role in understanding the high density matter in the interiors of neutron/hybrid stars. At their high densities, additionally, both proton superconductivity and neutron superfluidity are expected. We study the effect of superconducting (quark/proton) matter, along with the internal magnetic field, leading to pressure anisotropy within hybrid stars. We aim to probe the effect of superconductivity, especially from color superconducting quarks, in hybrid star structure. We propose new phenomenological model anisotropy profiles within a one-dimensional framework. We model quark matter using the vector interaction enhanced Bag model, and hadron matter with the DD2 equation of state. A Maxwell construction joins both phases. We further investigate the possible observational signatures of these hybrid stars. These include mass enhancement and continuous gravitational waves, possibly arising from the anisotropy induced deformation, helping us further constrain our model and its physical parameters.