Neutron star in elliptical orbit about a black hole

Abstract

A neutron star in an elliptical orbit about a black holes is disrupted as it passes near the black hole. Its apparent spin after the encounter is not really rotation: Without shocks, circulation is exactly preserved. Instead of rotation, what you are seeing is a nonaxisymmetric mode, a nonlinear version of a bar mode. Interactions of this kind may be common enough in globular clusters and the centers of galaxies for the advanced gravitational wave detectors LIGO/VIRGO and KAGRA to observe the gravitational waves they emit.