A Black Hole Drove a Star Out of the Milky Way and Caught its Partner

A star fleeing the Milky Way at an incredible speed was discovered by a group of scientists, who cataloged it as the fastest.

However, they have just been able to identify the cause of their vertiginous escape: the culprit is the supermassive black hole Sagittarius A*, located in the center of our galaxy.

Sergey Koposov, from Carnegie Mellon University, was the first to observe the star S5-HVS1, which was traveling at a speed of 1800 kilometers per second.

After months of studies, the astronomer concludes that the star was part of a binary system, that is, it had a partner; but they got too close to Sagittarius A*.

The gravitational attraction of the black hole can interact in two ways with the approaching bodies depending on their mass and speed: either it captures them or expels them.

After this interaction, the companion was trapped in the orbit of Sagittarius A*, while S5-HVS1 was shot so hard that it left the disk of our galaxy.

“This is super exciting, since we have long suspected that black holes can eject stars with very high speeds.

However, we never had an unequivocal association of such a fast star with the Galactic Center,” said Koposov.

The astrophysicist estimates that the supermassive black hole expelled the star with a speed of thousands of kilometers per second about five million years ago, “when the ancestors of humanity were learning to walk on two feet.”

After finding the star 29,000 light years away from Earth, the scientists tracked their journey from the center of the galaxy thanks to the Hills Mechanism , which explains how super fast stars are ejected by black holes.

“This is the first clear demonstration of the Hills mechanism in action,” said Ting Li, leader of the S5 Collaboration team , which detected the star in its closest approach to our planet.

“Seeing this star is really amazing,” he added, “because we know it must have formed in the Galactic Center, a place very different from our local environment.

He is a visitor from a strange land. ”

The detection of the star was possible thanks to the AAT telescope in Australia, together with the observations of the Gaia satellite of the European Space Agency (ESA), which allowed to calculate the maximum speed of the star and its trip from the heart of our galaxy.




Source: Larepublica