Last year, astronomers saw the violent death throes of a star as it was literally torn apart by a black hole (see here, and links within). And now, they’ve seen it again: observations across the electromagnetic spectrum caught another star that wandered too close to a supermassive black hole, and suffered the ultimate fate.
These observations show the before-and-after (left versus right) of the event. The top two are from GALEX, a satellite that observes the skies in the ultraviolet, and the bottom using Pan-STARRS1, a powerful telescope (located on which mountain, you ask? Why, Haleakala in Hawaii, of course) that scans the entire night sky looking for transients, things that change brightness.
The light from the star’s violent demise reached us in June of 2010. The event happened in the heart of a distant galaxy, 2.7 billion light years away. At the center of that galaxy is a black hole with millions of times the Sun’s mass, comparable to the black hole in the center of our own Milky Way galaxy. The star apparently orbited the black hole in an elliptical orbit. Over millions or billions of years, the star evolved, and turned into a red giant. Over time, its orbit tightened, and one day it got too close. The enormous tides of the black hole tore the star apart.
The flare happened when the stellar material spiraled into the hole. It formed a flattened disk right before the Ultimate Plunge, which got very hot and blasted out high-energy light — the ultraviolet light from this galaxy flared 350 times brighter than it was before! Some of the material from the star was also flung away into space. Astronomers put together a nifty video simulating what happened: