Five million years ago, when humanity's ancestors only learned to walk upright, a star was pulled out of Sagittarius A * the super-massive black hole in the middle of the Milky Way, at a staggering 3.7 million km / h This month, a group of scientists discovered 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 Stellar Stream Spectroscopic Survey (S5), saw the star – known as S5-HVS1 – in the constellation Gravel. According to a press release Tuesday, the star travels just 29,000 light-years away from Earth, or "practically next door to astronomical standards."
Scientists said that the "leap" star traveled at speeds about 10 times faster than most other stars in the galaxy. "The speed of the detected star is so high that it will inevitably leave [Milky Way] and will never return," said co-author Douglas Boubert of the University of Oxford.
"This is extremely exciting, as we have long suspected that black holes can eject stars at very high speeds," Koposov said. "But we have never had an unambiguous association of such a fast star with the Galactic Center."  Astronomer Jack Hills first suggested that black holes can eject super-fast stars at high speed, but S5-HVS1 is the first time scientists have actually witnessed the Hills Mechanism in action.
The discovery was made using the 12.8-foot Anglo-Australian telescope and observations from the European Space Agency's Gaia satellite, the relative proximity of the star enabled an "outstanding" opportunity to learn about the phenomenon.
"Seeing this star is really amazing," said Carnegies Ting Li. "As we know it must have been formed in the Galactic Center, a place very different from our local environment. It is a visitor from a strange country."
Koposov and his team can now trace the star's journey back to the center of the galaxy . They assume that the S5-HVS1 used to live with a companion, but when the two drove too close Sagittarius A * its companion was captured while being thrown out again.
"My favorite part of this discovery is thinking about where this star came from and where it is going," said Carnegie's Alex Ji. "It was born in one of the craziest places in the universe, near a super-massive black hole with lots of other nearby star friends; but it will leave our galaxy and die completely alone, out in the middle of nowhere. Quite a case from grace."