Posted on behalf of Adam Mann

The black hole at the center of our Milky Way galaxy likes to play peculiar games. Almost 100 million years ago, it flung a unique star away from the galactic center at nearly two million miles per hour, according to paper published online on 20 July in Astrophysical Journal Letters.

The star, named HE 0437-5439, stands out of the crowd; it contains nine times the mass of our sun, is currently 200,000 light-years from the galactic core (five times the average star’s distance), and is one of only 16 stars classified as a hypervelocity star due to its speed.

Researchers at the University of Michigan in Ann Arbor used data from NASA’s Hubble telescope to trace the zooming behemoth’s trajectory back to its original home in the galactic core. The star’s tremendous speed, they say, could be a result of slingshotting around the galaxy’s central black hole.

This odd origin story suggests that the star is bizarre in another way: even traveling at blinding speed, the star would need 100 millions years to reach its current position. But massive stars are short-lived creatures and HE 0437-5439 should have burned itself out after just 20 million years.

Given that revelation, the researchers believe that this huge, speeding star is actually a “blue straggler” – two smaller, longer-lived stars that later merged into one.

They suggest that 100 million years ago, a triple star system wandered too close to the galaxy’s central black hole. The black hole grabbed one of the three but sent the other two flying out into space at tremendous speed.

Image Credit: NASA, ESA, and G. Bacon (STScI)