2006/09/30 by Ryan M. O’Leary, Ryan M. O'Leary, Abraham Loeb · 3 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2007.12531.x
8 pages, 3 figures. Accepted for publication in MNRAS. Some major changes to text, however conclusions remain the same
arxiv created 2007/10/02 · openalex publication_date 2007/11/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Stars within 0.1 pc of the supermassive black hole (BH) Sgr A* at the Galactic Centre are expected to encounter a cluster of stellar-mass BHs that have segregated to that region. Some of these stars will scatter off an orbiting BH and be kicked out of the Galactic Centre with velocities up to ∼2000 km s−1. We calculate the resulting ejection rate of hypervelocity stars (HVSs) by this process under a variety of assumptions, and find it to be comparable to the tidal disruption rate of binary stars by Sgr A*, first discussed by Hills. Under some conditions, this novel process is sufficient to account for all of the hypervelocity B stars observed in the halo, and may dominate the production rate of all HVSs with lifetimes much less than the relaxation time-scale at a distance ∼2 pc from Sgr A* (≳2 Gyr). Since HVSs are produced by at least two unavoidable processes, the statistics of HVSs could reveal bimodal velocity and mass distributions, and can constrain the distribution of BHs and stars in the innermost 0.1 pc around Sgr A*.