Astronomers discovered 591 high-velocity stars

43 of them can even escape from the Galaxy.

After the first high-velocity star was discovered in 2005, over 550 ones have been discovered with multiple telescopes in 15 years.

Now an exploration group, driven by astronomers from the National Astronomical Observatories of Chinese Academy of Sciences (NAOC), has found 591 high-velocity stars dependent on data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and Gaia, and 43 of them can even escape from the Galaxy.

Dr. Li Yinbi, lead author of the study, said, “The 591 high-velocity stars discovered this time doubled the total number previously discovered, bringing the current total number exceeding 1,000.”

Prof. LU Youjun from NAOC, a co-author of this paper, said, “High-velocity stars are fast-moving stars, and they can even escape from the Galaxy. Though rare in the Milky Way, high-velocity stars, with unique kinematics, can provide deep insight into a wide range of Galactic science, from the central supermassive black hole to distant Galactic halo.”

Prof. Luo Ali from NAOC, a co-author of this research, said, “Databases from LAMOST and Gaia provide us unprecedented opportunity to find more high-velocity stars, and we did it.”

“From the kinematics and chemistries, we found that the 591 high-velocity stars were inner halo stars.”

Prof. Zhao Gang from NAOC, a co-author of the study, said“Their low metallicities indicate that the bulk of the stellar halo formed as a consequence of the accretion and tidal disruption of dwarf galaxies.”

The discovery of these high-velocity stars tells us that the combination of multiple large surveys in the future will help us to discover more high-velocity stars and other rare stars, which will be used to study the mystery about our Galaxy.

Journal Reference:
  1. Yin-Bi Li et al. 591 High-velocity Stars in the Galactic Halo Selected from LAMOST DR7 and Gaia DR2, The Astrophysical Journal Supplement Series (2020). DOI: 10.3847/1538-4365/abc16e

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