Discovery of a nearby 1700 km s−1 star ejected from the Milky Way by Sgr A*

@article{Koposov2019DiscoveryOA,
  title={Discovery of a nearby 1700 km s−1 star ejected from the Milky Way by Sgr A*},
  author={Sergey E. Koposov and Douglas Boubert and Ting S. Li and Denis Erkal and Gary Da Costa and Daniel B. Zucker and Alexander P. Ji and Kyler W. Kuehn and Geraint F. Lewis and Dougal Mackey and Jeffrey D. Simpson and Nora Shipp and Zhen Wan and Vasily A Belokurov and Joss Bland-Hawthorn and Sarah L. Martell and Thomas Nordlander and Andrew B. Pace and Gayandhi M. De Silva and Mei-Yu Wang},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2019}
}
We present the serendipitous discovery of the fastest main-sequence hyper-velocity star (HVS) by the Southern Stellar Stream Spectroscopic Survey (S5). The star S5-HVS1 is a ∼2.35 M⊙ A-type star located at a distance of ∼9 kpc from the Sun and has a heliocentric radial velocity of 1017 ± 2.7 $\mathrm{\, km\, s^{-1}}$ without any signature of velocity variability. The current 3D velocity of the star in the Galactic frame is 1755 ± 50 $\mathrm{\, km\, s^{-1}}$. When integrated backwards in time… 

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