Hyper-velocity and tidal stars from binaries disrupted by a massive Galactic black hole

Abstract

A close but newtonian encounter between a tightly bound binary and a 106 M⊙ black hole causes one binary component to become bound to the black hole and the other to be ejected at up to 4,000 km−1. The discovery of even one such hyper-velocity star coming from the Galactic centre would be nearly definitive evidence for a massive black hole. The new companion of the black hole has a high orbital velocity which increases further as its orbit shrinks by tidal dissipation. The gravitational energy released by the orbit shrinkage of a such a tidal star can be comparable to its total nuclear energy release