Magnetically supramassive and hypermassive compact stars

TL;DR

This paper uses numerical simulations to explore highly magnetized compact stars, revealing solutions that surpass traditional mass limits due to strong magnetic fields, including supramassive and hypermassive configurations.

Contribution

It systematically computes equilibrium solutions of magnetized compact stars with mixed magnetic fields, identifying new supramassive and hypermassive states beyond known mass limits.

Findings

Magnetically supramassive solutions exceed 10% of maximum non-magnetized mass.

Strong magnetic fields can produce hypermassive stars beyond Kepler limit.

Numerical code COCAL effectively models these extreme configurations.

Abstract

It is known that the mass of magnetized relativistic compact star is larger than that of non-magnetized one for the same equation of state and central density, albeit the excess of mass is sizable only if the magnetic fields are strong enough B~10^17-10^18G. Using our recently developed numerical code COCAL, we systematically compute such compact star solutions in equilibrium associated with mixed poloidal and toroidal magnetic fields, and show the magnetically supramassive solutions whose masses exceed by more than 10% of the maximum mass of the static and spherically symmetric solutions. For some extremely strong magnetic field configurations, we also obtain solutions more massive than the maximum mass of the uniformly rotating solutions at the Kepler (mass-shedding) limit, namely magnetically hypermassive solutions.