Five million years ago, when the ancestors of humanity were just learning to stand, a star was kicked out of, the supermassive black hole in the center of the Milky Way, at an incredible 3.7 million mph. This month, a group of researchers saw the super-fast star traveling relatively close to Earth.
Researchers, led by Sergey Koposov of Carnegie Mellon University's McWilliams Center for Cosmology, as part of the Southern Star Flow Spectroscopic Research (S5), spotted the star – known as the S5-HVS1 – in the Grus constellation. According to a press release on Tuesday, the star was only traveling just 29,000 light years from Earth, or "practically by astronomical standards."
Researchers said the "runaway" star was traveling at speeds 10 times faster than most other stars in the galaxy. "The speed of the discovered star is so high that it will inevitably leave the [Milky Way] and never come back, "said co-author Douglas Boubert of Oxford University.
"This is super exciting because we have long suspected that black holes can eject stars at very high speeds," said Koposov. "However, we have never had an unambiguous association of such a fast star with the Galactic Center."
Astronomer Jack Hills first proposed thatcan eject super fast stars at high speeds. But S5-HVS1 is the first time scientists have witnessed Hills Mechanism in action.
The discovery was made using the 12.8 ft Anglo-Australian Telescope and observations from the European Space Agency's Gaia satellite. The star's relative proximity allowed an "unprecedented" opportunity to learn about the phenomena.
"Seeing this star is really amazing," said Carnegie's Ting Li. "As we know, it must have formed at the Galactic Center, a very different place from our local environment. It's a visitor from a strange land."
Koposov and his team can now follow the star's journey back to the. They hypothesize that the S5-HVS1 lived with a companion star, but when they got too close to , his mate was captured and thrown back.
"My favorite part of this discovery is thinking about where this star came from and where it's going," said Carnegie's Alex Ji. "It was born in one of the craziest places in the universe, near a supermassive black hole with many other close stellar friends; but it will leave our galaxy and die alone in the middle of nowhere. Grace."