Limiting magnetic field for minimal deformation of a magnetised neutron star

Understand

In this work we study the structure of neutron stars under the effect of a poloidal magnetic field and determine the limiting highest magnetic field intensity which still allows a satisfactory description of magnetic neutron stars in the spherical symmetry regime.

• We describe different compositions of stars (nucleonic, hyperonic, and hybrid), using three state-of-the-art relativistic mean field models for the microscopic description of matter, which are in agreement with experimental and observational data.
• The structure of stars is described by the general relativistic solution of both Einstein's field equations assuming a spherical symmetry, and Einstein-Maxwell's field equations assuming an axi-symmetric deformation.
• We find a limiting magnetic moment of the order of $2\times 10^{31}$Am$^2$, which corresponds to magnetic fields of the order of 10$^{16}$ G at the surface, and $ \sim 10^{17}$ G at the centre of the star, above which the deformation due to the magnetic field is not negligible.