Strong magnetic fields: neutron stars with an extended inner crust

TL;DR

This study uses relativistic mean-field models to show that strong magnetic fields can extend the inner crust of neutron stars by promoting pasta phases and affecting the structure of clusterized matter, with implications for crust stability.

Contribution

It demonstrates that intense magnetic fields induce pasta phases at higher densities and significantly influence the structure of neutron star inner crusts, extending previous predictions.

Findings

Pasta phases occur at higher densities under strong magnetic fields.

The inner crust extension is larger than previously thought.

Magnetic field decay can cause internal stresses leading to crust fractures.

Abstract

Using relativistic mean-field models, the formation of clusterized matter, as the one expected to exist in the inner crust of neutron stars, is determined under the effect of strong magnetic fields. As already predicted from a calculation of the unstable modes resulting from density fluctuations at subsaturation densities, we confirm in the present work that for magnetic field intensities of the order of $\approx 5 \times 10^{16}$ G to $5 \times 10^{17}$ G, pasta phases may occur for densities well above the zero-field crust-core transition density. This confirms that the extension of the crust may be larger than expected. It is also verified that the equilibrium structure of the clusterized matter is very sensitive to the intensity of the magnetic fields. As a result, the decay of the magnetic field may give rise to internal stresses which may result on the yield and fracture of the inner crust lattice.