April 2, 2013
Distant Black Hole Awakens To Devour Massive Planet
Watch the video "Black Hole Eats Super-Jupiter"
Lee Rannals for redOrbit.com - Your Universe Online
Astronomers using the European Space Agency's (ESA) Integral space observatory have watched as a black hole woke up to feed on a low-mass object that strayed just a little too close.
The team was using the Integral observatory to study a galaxy 47 million light-years away when they noticed a bright X-ray flare coming from another location.
"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 which appeared recently in the journal Astronomy & Astrophysics.
The team analyzed the characteristics of the flare and determined the emission came from a halo of material around the galaxy's central black hole as it tore apart an object the size of about 14 to 30 Jupiter masses. The size corresponds to that of a brown dwarf star, which are substellar objects that are not massive enough to fuse hydrogen in their core.
The authors added it could have had an even lower mass — just a few times that of Jupiter — which could make it a gas-giant planet. Free-floating planetary objects of this kind may occur in large numbers in galaxies, ejected from their parent solar systems by gravitational interactions.
Astronomers said the black hole in galaxy NGC 4845 is about 300,000 times the mass of our Sun. They said the emission given off as it consumed its food brightened and decayed for two to three months, showing an intermittency as it seems to just nibble around at the object.
"This is the first time where we have seen the disruption of a substellar object by a black hole,” adds co-author Roland Walter of the Observatory of Geneva, Switzerland. "We estimate that only its external layers were eaten by the black hole, amounting to about 10% of the object´s total mass, and that a denser core has been left orbiting the black hole.”
Astronomers are comparing this to what will possibly be happening in a supermassive black hole at the center of our own Milky Way Galaxy later this year. A compact gas of just a few Earth masses has been spiraling towards the black hole and could soon meet a similar fate.
"Estimates are that events like these may be detectable every few years in galaxies around us, and if we spot them, Integral, along with other high-energy space observatories, will be able to watch them play out just as it did with NGC 4845,” says Christoph Winkler, ESA´s Integral project scientist.
Scientists have created a supercomputer simulation to determine that the cloud could possibly partially survive the encounter with the black hole.
"It will lose a lot of its energy but not all of it,” computational physicist Peter Anninos said in The Astrophysical Journal. "It will become so diffuse that it´s unlikely that any remnant of the gas will continue on its orbital track.”