Chinese astronomers discover 591 high-velocity stars

A team of scientists, led by Chinese astronomers from National Astronomical Observatories of Chinese Academy of Sciences (NAOC) has discovered 591 high velocity stars.

The discovery was made using data from the European Space Agency’s (ESA) Gaia spacecraft and Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST).

Out of 591, forty three high velocity stars can even escape from our galaxy Milky Way.

First high velocity star was discovered in 2005, since then over 550 have been discovered by various telescopes. And now this new discovery doubled the total number of known high velocity stars with numbers going above 1,000.

A star moving faster than sixty five kilometres per second to hundred kilometres per second comparative to the normal motion of the stars in our Sun’s neighbourhood is a high velocity star.

The 3 types of high velocity stars are- halo stars, runaway stars, and hypervelocity stars. Some of the hypervelocity stars can even exceed the Milky Way’s escape velocity.

According to scientists- with their unique kinematics, high velocity stars can provide profound understanding of Galactic science.

By studying kinematics and chemistry of these stars, scientists found that these 591 high velocity stars were inner halo stars.

The low metallicities of the stars suggest that the majority of the stellar halo formed as a result of the tidal disruption and accretion of the dwarf galaxies.

Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) is the largest optical telescope in China. It is also called Guo Shoujing Telescope- named after the thirteenth century Chinese astronomer.

Gaia is European Space Agency’s (ESA) space telescope. It was launched in 2013 and expected to remain functional until 2022. The space telescope is designed for astrometry- taking measurements of positions, distances and motions of stars in extreme precision.

For more details: 591 High-velocity Stars in the Galactic Halo Selected from LAMOST DR7 and Gaia DR2



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