Star spotted flying through universe at blistering speed after being thrown out by black hole

Object 'is a visitor from a strange land', scientist says

A star has been spotted speeding through the universe after it was thrown by a supermassive black hole.

It is going so fast that it will eventually be thrown out of the galaxy and never return, scientists said.

The star was thrown out of the black hole at the centre of our galaxy, known as Sagittarius A*. As such, scientists describe it as "a visitor from a strange land", having come relatively near to us from the very middle of our Milky Way.

The star was spotted in the constelltion of Grus, or the crane, by researchers from Carnegie Mellon University. They saw that the star was moving 10 times faster than most of the stars in our galaxy, and looked to study it for more information.

"The velocity of the discovered star is so high that it will inevitably leave the galaxy and never return," said Douglas Boubert from the University of Oxford, a co-author on the study.

High velocity stars of this kind were only discovered about 20 years ago, and remain mysterious to scientists. This is the first star of its kind ever seen, with astronomers never spotting one of the mysterious stars so fast and close by before.

The object passed by a mere 29 thousand light years away. Astronomers were able to track its journey back to the beginning, at the middle of the Milky Way – where a huge black hole known as Sagittarius A* can be found.

"This is super exciting, as we have long suspected that black holes can eject stars with very high velocities. However, we never had an unambiguous association of such a fast star with the galactic center," said Koposov, the lead author of this work and member of Carnegie Mellon's McWilliams Center for Cosmology.

"We think the black hole ejected the star with a speed of thousands of kilometers per second about five million years ago. This ejection happened at the time when humanity's ancestors were just learning to walk on two feet."

The star began as one half of a binary system, but the two stars drifted too close to the extreme environment of Sagittarius A*. As they fell into the intense gravitational environment around the black hole, the companion star was eaten up, but the newly discovered one was thrown out at incredible speed through a process known as the Hills Mechanism.

"This is the first clear demonstration of the Hills Mechanism in action," said Ting Li from Carnegie Observatories and Princeton University, and leader of the S5 Collaboration. "Seeing this star is really amazing as we know it must have formed in the galactic center, a place very different to our local environment. It is a visitor from a strange land."