Closest Bright Hypervelocity Star ' LAMOST -HVS1' Discovered

A hypervelocity star has been discovered that offers clues about the supermassive black hole at the center of our galaxy including the dark matter surrounding our galaxy.

Researchers at the University of Utah discovered a 'hypervelocity star' dubbed LAMOST -HVS1 that is known to be the second brightest and the closest among the massive 20 detected till date.  The newly identified hypervelocity star is seen speeding at over 1 million miles per hour. According to the astronomers, this star offers insight into the supermassive black holes at the center of Milky Way and the halo of the dark matter encircling the galaxy.

"The hypervelocity star tells us a lot about our galaxy - especially its center and the dark matter halo," said Zheng Zheng, an assistant professor of physics and astronomy and lead author of the study. "We can't see the dark matter halo, but its gravity acts on the star. We gain insight from the star's trajectory and velocity, which are affected by gravity from different parts of our galaxy."

The star was discovered during research into stars with Large Sky Area Multi-Object Fiber Spectroscopic Telescope, or LAMOST, located at the Xinglong Observing Station of the National Astronomical Observatories of China. The star is located at 249 quadrillion miles away from Earth.

LAMOST captures the spectra from over 4000 stars at once and this spectrum offers details on the velocity, temperature, size and luminosity of the star. Over the past decade, astronomers hunted 20 such odd stars. 

"Hypervelocity stars appear to be remaining pairs of binary stars that once orbited each other and got too close to the supermassive black hole at the galaxy's center. Intense gravity from the black hole - which has the mass of 4 million stars like our sun - captures one star so it orbits the hole closely, and slingshots the other on a trajectory headed beyond the galaxy," astronomers explain.

Due to its unusual speed, the researchers could easily detect the hypervelocity star. It is three times the speed of a usual star i.e.  500,000-miles per hour pace through space.

A cluster of hypervelocity stars including LAMOST-HVS1 are situated above the disk of our galaxy.  Based on their distribution in the sky it appears that the stars originated near the center of the galaxy.

As the hypervelocity star travels through the dark matter halo, its speed and trajectory gives astronomers a peak into the mysterious halo. This star is 630 times dimmer than the stars that can be barely viewed by the human naked eye.  It is one of the three massive hypervelocity stars ever discovered.

Since it is nine times more massive than the sun it is similar to another hypervelocity star called HE 0437-5439 that was discovered in 2008. This hypervelocity star outshines our Sun and is four times hotter and 3,400 times brighter.