Big Gulp: Flaring Galaxy Marks the Messy Demise of a Star in a Supermassive Black Hole
A close look at a distant cataclysm indicates that the black hole’s victim was a red giant star
Once in a while, a supermassive black hole gets a sumptuous treat. A passing star wanders too close and gets caught in the black hole’s gravitational pull, like a fly trapped in a spider’s web. The star then becomes an easy meal for the black hole, which tears its prey to bits and ingests a good portion of it.
Astronomers have witnessed several such disruptions before in distant galaxies, but usually only toward the end of the process. (These feedings are far too rare, however, to have been witnessed in our own Milky Way anytime in recent human history; they occur only once every 10,000 years or so per galaxy.) Now researchers have documented a black hole’s feasting in such detail that they were able to infer its size as well as the type of star that fell prey to its gluttony.
Astronomers cannot peer inside a black hole itself; beyond the event horizon, a black hole’s point of no return, even light cannot escape into the outside world. But material falling into a black hole gives off intense flares of radiation as it compresses and heats up outside the event horizon.
Suvi Gezari, an astronomer at Johns Hopkins University, and her colleagues used a number of different telescopes to track the outburst from a supermassive black hole in a galaxy more than two billion light-years away as the black hole consumed a star that ventured too close.
“While there has been evidence of these types of flares before, there’s never been enough information to say what kind of star fell victim to the black hole, and what was the mass of the black hole that destroyed the star,” Gezari says. She and her colleagues published their findings online May 2 in Nature.
61
