Hypervelocity Stars

Dr. Warren R. Brown, Smithsonian Astrophysical Observatory

Hypervelocity stars are ejected by the Galaxy’s central massive black hole at speeds that exceed Galactic escape velocity. We discovered the first hypervelocity star in 2005, and have since found many more unbound stars in a targeted survey. The stars are interesting because their distributions in space and velocity are linked to the black hole ejection mechanism. The 3D trajectories of the stars — which travel from the very center to the outer halo — are potentially unique probes of the Galaxy’s dark matter distribution.