Initialization of Compact Star Orbits Using External Potential Relaxation Scheme

Studying the mergers of compact-star binaries is essential for testing fundamental physics including the behavior of nuclear matter at high densities and in strong gravitational fields. Such studies are typically performed with computational fluid dynamics codes which require accurate initial conditions in regard to the shapes of each star in orbit to correctly model the inspiral phases and accretion flows. In this talk, we discuss a method which applies external potentials to relax binary neutron star and white dwarf configurations to be used as initial setups in Newtonian Smoothed Particle Hydrodynamics simulations. The external potential is defined so that the resulting forces which are experienced by the stars correspond to accelerations in a frame that is corotating with the binary. The forces deform each star to the configuration they should have, given a defined spin and orbital separation. We discuss the effectiveness of the method to produce stable Newtonian orbits as well as potential applications where we explore behavior of solid components in a neutron star's crust or core and their impact on the inspiral phase of a binary.