Star Kicked Out By Milky Way's Black Hole Leaving At 'Record-Breaking' Speed

Astronomers from the Australian National University (ANU) Siding Spring Observatory were searching for remains of small galaxies orbiting the Milky Way when they discovered a star hurtling through the galaxy at record-breaking speeds. Where did it come from and why is it moving 10 times faster than most stars in the Milky Way?

The astronomers found that the fast-moving star actually originated from the center of the Milky Way where it was kicked out by supermassive black hole Sagittarius A, which is 4.2 million times more massive than the sun in our solar system.

Evidently, such a phenomenon that can happen when a binary stellar system comes too close to the black hole that it captures one of the stars and throws it out of the galaxy at high speeds. In the case of this star, the astronomers say that the eviction happened 5 million years ago and it was observed to be moving at incredible speeds of 3,728,227 mph ( 5,999,999.75 kph).

“The star is only29,000 light years away, quite close by galactic standards, which means the team could measure its trajectory very precisely,” said Dr. Dougal Mackey of ANU who was involved in the study along with other astronomers from Australia, U.S., U.K. and Chile.

Based on their observations, the astronomers believe the star will finally be out of the galaxy in 100 million years.

“In astronomical terms, the star will be leaving our galaxy fairly soon and it will likely travel through the emptiness of intergalactic space for eternity,” said Emeritus Professor Gary Da Costa of ANU Research School of Astronomy and Astrophysics.

Apparently, while there are other observed “hyper velocity” stars, this particular star is rather unique because it is moving at speeds much faster than other hyper velocity stars, and because the astronomers are almost certain that it came from the center of the galaxy.

Because of these characteristics, astronomers were able to confirm the theorized way of how the black hole at the center of Milky Way can throw out stars from the galaxy at very high speeds, evictions that are theorized to occur every few hundred thousand years.

In the case of the evicted star, it will never return to the Milky Way once it leaves the galaxy in 100 million years.

The paper about the discovery is published in Monthly Notices of the Royal Astronomical Society.