Ejection of Hypervelocity Stars by the (Binary) Black Hole in the Galactic Center

  title={Ejection of Hypervelocity Stars by the (Binary) Black Hole in the Galactic Center},
  author={Qingjuan Yu and Scott Tremaine},
  journal={The Astrophysical Journal},
  pages={1129 - 1138}
We study three processes that eject hypervelocity (>103 km s-1) stars from the Galactic center: (1) close encounters of two single stars, (2) tidal breakup of binary stars by the central black hole, as originally proposed by Hills, and (3) three-body interactions between a star and a binary black hole (BBH). Mechanism 1 expels hypervelocity stars to the solar radius, R0 = 8 kpc, at a negligible rate, ~10-11 yr-1. Mechanism 2 expels hypervelocity stars at a rate ~10-5(η/0.1) yr-1, where η is the… 
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