SSS 2010-07-23（在线收听）

Here’s what scientists think happened, oh, about a hundred million years ago. There was this three-star system. The three linked stars were strolling through the galaxy but got too close to the giant black hole at the center. The hole swallowed one of those stars and hurled away the other two. Those two careening stars merged to form one super-hot, incredibly fast-moving blue star, which is now on the very outskirts of the Milky Way.

And here’s how scientists came up with that dramatic tale, which they just published in Astrophysical Journal Letters.

They discovered what they call a hypervelocity star, which moves three times faster than our sun does through the galaxy. According to new information provided by the Hubble telescope, the star originated deep within the Milky Way.

The scientists used the Hubble to figure out the direction of the star’s travels and the distance from the galactic center, along with the star’s mass, age and speed. Its unusual attributes give rise to the idea that one star was swallowed and transferred its momentum to the other two, which transformed into a blue superstar. Hurtling through the galaxy, faster than a speeding sun.

Thanks for the minute for Scientific American’s 60-Second Science. I’m Cynthia Graber