BLACK holes are picky, swallowing some stars and spitting out others.
Models show that when a binary star approaches a supermassive black hole, one star may fall in while the other is flung out at about 1000 kilometres per second. Several such "hypervelocity stars" have so far been detected, but their precise origin was unclear.
Now Warren Brown of the Harvard-Smithsonian Center for Astrophysics and colleagues have used red-shift data and Hubble Space Telescope images to trace the path taken by the hypervelocity star HE 0437-5439. It points back to the centre of the galaxy, so the huge black hole thought to exist there may have hurled the star out (The Astrophysical Journal Letters, in press).
To continue reading this article, subscribe to receive access to all of newscientist.com, including 20 years of archive content.