An artist's impression of runaway stars.
Credit: Amanda Smith
The speediest stars zipping through the Milky Way galaxy are runaways from a small neighboring galaxy, according to a new study.
Scientists said they suspect that around 10,000 of these so-called "hypervelocity" stars in the Milky Way were born in a small satellite galaxy known as the Large Magellanic Cloud. Each of those stars was once half of a binary star system, in which two stars orbit one another. But explosive breakups sent the stars flying away so fast that they escaped the gravitational pull of their home galaxy and ventured off into the Milky Way, the study suggests.
Using data from the Sloan Digital Sky Survey, researchers from the University of Cambridge in the United Kingdom created computer simulations of these swift intergalactic stars, demonstrating how the explosion of one star in a binary can send the other packing fast enough to be ejected from the Large Magellanic Cloud. [Top 10 Star Mysteries]