### Neutron Stars

The initial, equal-mass neutron stars are modeled as irrotational, unmagnetized, $\Gamma = 2$ polytropes. We evolve the hydrodynamic and metric fields up until two orbits prior to tidal disruption, at which point the NS is seeded with a dynamically weak, dipolar B-field generated by the vector potential $A_\phi$, which approximates the vector potential of a current loop. We choose the current and radius of the loop such that, in the interior, the maximum value of the ratio of magnetic to gas pressure is $\beta^{-1} = 0.003125$, which is dynamically weak and does not affect the evolution. The field in the exterior magnetosphere is strong, with $\beta^{-1} \lesssim 100$, and mimics the force-free conditions likely characterizing such a region.