Stationary, axisymmetric neutron stars with meridional circulation in general relativity

We present the first stationary, axisymmetric neutron star models with meridional circulation in general relativity. For that purpose, we developed generally rotating neutron star, a new code based on a fixed-point iteration. We find a two-dimensional set of meridional circulation modes, which differ by the number of vortices in the stream lines of the neutron star fluid. For expected maximal meridional circulation velocities of about 1000 km/s, the vortices cause surface deformations of about a percent. The deformations depend on the shape of the vortices close to the surface and increase with the meridional circulation velocity. We also computed models of rotating neutron stars with meridional circulation, where neither the surface rotates nor does the rotation velocity exceed the circulation velocity.