Astronomers watching a distant galaxy were stunned to see a black hole wake up like a hibernating bear, look around for a snack, then swallow a giant planetary structure that happened to venture too close.
The phenomenon was spotted in NGC 4845, a galaxy located 47 million light-years from Earth, by the European Space Agency's INTEGRAL space observatory.
Astronomers from NASA then confirmed the discovery with the Swift space telescope, as did Japan using its MAXI X-ray monitor aboard the International Space Station.
It marks the first time astronomers have watched a black hole devour a sub-stellar object. The findings were detailed in a study published this week in the journal Astronomy & Astrophysics.
The astronomers weren't even looking at NGC 4845, but were studying a different galaxy altogether when a bright flare caught their attention.
"The observation was completely unexpected, from a galaxy that has been quiet for at least 20-30 years," said Marek Nikolajuk of the University of Bialystok, Poland, lead author of the paper, in a statement released by the ESA.
The light in the galaxy brightened by 1,000 times at the height of the observations in January 2011, then subsided over the course of the year as astronomers kept watch.
Intrigued by the powerful flare, located in an area that astronomers had previously paid little attention to, researchers began taking a closer look at the characteristics of the blast.
They were able to determine that the emission originated form a halo of material clustered around NGC 4854's central black hole as it absorbed a planetary structure estimated to be 14 to 30 times the size of Jupiter. The object has the characteristics of a brown dwarf -- an object that is not large enough to fuse hydrogen and therefore ignite and achieve star status.
However, astronomers concede the structure could be much smaller than they estimate, possibly just two to three times the mass of Jupiter, which could change its classification to a "gas-giant planet," according to a statement from the ESA.
The black hole that swallowed the object is believed to have a mass roughly 300,000 times that of the sun.
"It also likes to play with its food: the way the emission brightened and decayed shows there was a delay of 2-3 months between the object being disrupted and the heating of the debris in the vicinity of the black hole," the statement said.
The astronomers believe the black hole tore away the outer layers of the brown dwarf or gas planet, stripping away about 10 per cent of its total mass. The denser core is thought to still be intact, possibly left orbiting the black hole.
The observations could have implications here in the Milky Way galaxy.
As early as this year, a supermassive black hole at the centre of our galaxy is expected to devour a gas cloud which has been spotted heading towards it.
The gas cloud is roughly three times the size of Earth and is expected to be devoured in a similar way to the object observed in NGC 4845 -- though on a much smaller scale.
"These events will tell astronomers more about what happens to the demise of different types of objects as they encounter black holes of varying sizes," the ESA news release said.
Watch the ESA animation depicting what astronomers believe took place:
