SIMBAD references

We study three processes that eject hypervelocity (>10³ km/s) 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. Mechanism 2 expels hypervelocity stars at a rate ∼10^–5(η/0.1)/yr, where η is the fraction of stars in binaries with semimajor axis a_b≲0.3 AU. For solar mass stars, the corresponding number of hypervelocity stars within the solar radius is ∼60(η/0.1)(a_b/0.1AU)^1/2. For mechanism 3, Sgr A* is assumed to be one component of a BBH. We constrain the allowed parameter space (semimajor axis, mass ratio) of the BBH. In the allowed region (for example, a semimajor axis of 0.5x10^–3 pc and a mass ratio of 0.01), the rate of ejection of hypervelocity stars can be as large as ∼10^–4/yr, and the expected number of hypervelocity stars within the solar radius can be as large as ∼10³. Hypervelocity stars may be detectable by the next generation of large-scale optical surveys.