Five million years ago, when human ancestors were just learning to walk upright, a star was released from there Sagittarius A *, a supermassive black hole at the center of the Milky Way Galaxy, with a speed of 3.7 million mph. This month, a group of researchers looked at super-fast stars that travel relatively close to Earth.
The researchers, led by Sergey Koposov of Carnwie Mellon University from McWilliams Center for Cosmology as part of the Southern Stellar Stream Spectroscopic Survey (S5), looked at the star – known as S5-HVS1 – in the Grus constellation. According to Tuesday's press release, the star only traveled only 29,000 light years from Earth, or "practically next to astronomical standards."
Researchers say the "runaway" star travels at about 10 times faster than most other stars in the galaxy. "The speed of the star found is so high that it will definitely leave a star [Milky Way] and never returned, "said co-author Douglas Boubert from the University of Oxford.
"This is very interesting, because we have long suspected that black holes can emit stars at very high speeds," Koposov said. "However, we have never had a clear connection between fast stars and the Galactic Center."
Astronomer Jack Hills first proposed that black hole can issue super fast stars at high speed. But S5-HVS1 is the first time scientists have actually witnessed 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 allows "unprecedented" opportunities to learn about the phenomenon.
"Seeing this star is truly extraordinary," said Ting Li from Carnegie. "As we know it must have formed at the Galactic Center, a place that is very different from our local environment. It is visitors from foreign lands."
Koposov and his team can now track star trips back to center of the galaxy. They hypothesized that S5-HVS1 was used to live with companion stars, but when both of them drifted too close to Sagittarius A *, his friend was arrested, while it was thrown back.
"My favorite part of this discovery is thinking about where this star came from and where it went," said Carnegie, Alex Ji. "He was born in one of the craziest places in the universe, near supermassive black holes with many other closest star friends; but he will leave our galaxy and die alone, in the middle of nowhere. Simply fall from grace."