Chinese astronomers discover 591 fast stars with LAMOST and Gaia

A research team led by astronomers from the National Astronomical Observatories of Chinese Academy of Sciences (NAOC) has discovered 591 high-speed stars based on data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and Gaia, and 43 of these can even escape from the Milky Way.

The research is published online in The Astrophysical Journal Supplement Series on December 17.

After the first high-speed star was discovered in 2005, more than 550 multiple telescopes have been discovered in 15 years. “The 591 high-speed stars discovered this time around doubled the total number previously discovered, bringing the current number to more than 1,000,” said Dr. Li Yinbi, lead author of the study.

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

LAMOST, the largest optical telescope in China, has the highest spectral acquisition rate in the world and can observe approximately 4,000 celestial targets in a single image. It started with regular surveys in 2012 and set up the largest spectra database in the world.

Gaia is a space mission in the European Space Agency (ESA) science program launched in 2013. It provided astrometric parameters for more than 1.3 billion sources, the largest database of astrometric parameters. “The two huge databases give us unprecedented opportunities to find more high-speed stars, and we have succeeded,” said Prof. Luo Ali of NAOC, a co-author of this study.

From kinematics and chemistry, the research team discovered that the 591 high-speed stars were inner halo stars. “Their low metallicity indicates that most of the halo of the stars was formed as a result of the growth and disturbance of the tide of dwarf galaxies,” said Prof. Zhao Gang of NAOC, a co-author of the study.

The discovery of these high-speed stars tells us that the combination of multiple major studies in the future will help us discover more high-speed stars and other rare stars that will be used to study the unsolved mystery about our Milky Way.