Fastest star leaving our galaxy was blasted out by a supernova

Most of the stars in our galaxy perform an orderly orbit around the galactic core. But, in recent years, researchers have discovered a class of stars that are moving remarkably quickly, in many cases fast enough to have achieved escape velocity—they'll eventually leave the Milky Way for intergalactic space.

What can account for a star moving at nearly 1,000 kilometers a second? One model involves our galaxy's supermassive black hole. When a binary star system gets drawn close to it, orbital interactions can leave one member of the binary orbiting the black hole, while slingshotting the other out of the system at high velocities. Several of the hypervelocity stars can have their paths traced back to the galactic core, providing support for this model.

But apparently not all. Researchers have revisited a hypervelocity star called US 708 and found that it's both the fastest moving star we've seen in our galaxy and that it didn't originate in the galactic core. Instead, the properties of the star suggest that it was blasted to its current speed by what's called a double-detonation supernova.