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A new class of ‘hypervelocity stars’ have been discovered that are moving fast enough to escape the gravitational grasp of the Milky Way galaxy.

“These new hypervelocity stars are very different from the ones that have been discovered previously,” said Lauren Palladino of Vanderbilt University in Tennessee, US, according to Zee News.

Originally the hypervelocity stars are larger blue stars and are thought to be originated from the galactic centre, but the new found star is relatively small, researchers noted.

“Our new stars are relatively small - about the size of the sun - and the surprising part is that none of them appear to come from the galactic core,” said Palladino.

The discovery of ‘hypervelocity stars’ came as astrophysicists were mapping the Milky Way and were calculating the orbits of sun-like stars.

“It’s very hard to kick a star out of the galaxy. That means when you trace the star back to its birthplace, it comes from the centre of our galaxy. None of these hypervelocity stars come from the centre, means there is an unexpected new class of hypervelocity star,” said Kelly Holley-Bockelmann who is an assistant professor of astronomy at Vanderbilt, according to Science Recorder. 

Researchers noted that in order to escape velocity, stars must receive more than a million mile per hour boost relative to the motion at which galaxy is moving. They estimated that the Milky Way’s central black hole weighs equivalent to 4 million suns which is large enough to produce a gravitational force that can accelerate stars to escape velocities.

The study is published in the Astrophysical Journal.