A Second Black Hole Found In The Milky Way
Via Space.com, Astronomers have discovered another black hole near the center of the Milky Way. This finding proves earlier speculation that black holes come in three sizes, small, medium and large. This new one, named GCIRS 13E, happens to be a medium size black hole.
Intermediate mass black holes ought to exist, some theorists say, because they should have been the building blocks of supermassive black holes. A few should be left scattered around any respectable galaxy. But attempts to discover them — data suggest two others exist in our galaxy — have so far proved inconclusive.
Black holes can’t be seen, because everything that falls into them, including light, is trapped. But the swift motions of gas and stars near an otherwise invisible object allows astronomers to calculate that it’s a black hole and even to estimate its mass.
If the newfound object, catalogued as GCIRS 13E, is indeed a middleweight black hole, it is likely a rare variety, perhaps one of kind, that formed farther out and has been lured to the galactic center. It is now less than 1.5 light-years from the fringes of the known supermassive black hole. That’s much closer than our Sun is to the next nearest star.
Orbiting the presumed middleweight are seven stars, each of which in its prime was more than 40 times the mass of the Sun. Even as corpses they contain five to 10 solar masses. The whole setup is racing around the galactic center at 626,300 mph (280 kilometers per second).
Theory holds that these stars could not have formed in their present location, because the gravity of the nearby supermassive black hole wouldn’t have allowed a gas cloud to contract into a star, says study leader Jean-Pierre Maillard of the Institute of Astrophysics in Paris.