Star Ejected By Milky Way's Supermassive Black Hole Clocked At 3.7 Million Miles Per Hour

(CBS Local) -- A runaway star traveling across our galaxy at an astonishing 3.7 million miles per hour is on track to be ejected from our Milky Way galaxy and into intergalactic space.

Astronomers believe the star, known as S5-HVS1, was part of a binary system, paired with another star, about 5 million years ago -- about the time when human ancestors first walked on two feet. That companion star was captured and swallowed up by a black hole while S5-HSV1 was launched away at thousands of miles per second.

The astronomers, whose findings are published in the journal Monthly Notices of the Royal Astronomical Society, say the star -- located in the constellation of Grus, or Crane -- is traveling about 10 times faster than most of the stars in the galaxy.

"The velocity of the discovered star is so high that it will inevitably leave the Galaxy and never return," co-author Douglas Boubert of the University of Oxford, said in a statement.

Because S5-HVS1 passed within 29,000 light-years of Earth, astronomers got a rare chance to observe the star and trace its footsteps back to the center of the Milky Way. There resides Sagittarius A*, a supermassive black hole that is four million times the mass of our sun.

"This is super exciting, as we have long suspected that black holes can eject stars with very high velocities. However, we never had an unambiguous association of such a fast star with the Galactic Center," said lead author Sergey Koposov of Carnegie Mellon University.