Hyperboloidal neutron star and black hole initial data in spherical symmetry

The focus of this work is on the construction of initial data including a neutron star on a hyperboloidal slice. As simplest scenario for this first step, spherical symmetry is considered together with a polytropic-like equation of state for the neutron star. Constraint-satisfying hyperboloidal initial data are obtained for a single neutron star and for a combination of neutron star with a black hole in its center. To the author's best knowledge this is the first time that full hyperboloidal slices of a neutron star spacetime are constructed. The obtained initial data are suitable for evolutions of the Einstein and relativistic hydrodynamic equations on hyperboloidal slices.