Frozen Neutron Stars

We investigate neutron stars with nonlinear magnetic monopoles in the framework of the Einstein-nonlinear electrodynamics model, specifically within the Bardeen and Hayward models. Solving the modified Tolman-Oppenheimer-Volkoff equations for three different equations of state, we find that upon reaching the critical magnetic charge $q_{c}$, neutron stars enter frozen states characterized by the critical horizon. This extends the concept of frozen states to compact objects composed of ordinary matter (non-field matter), thereby offering a new perspective for related research.