spacetoday.net: Stellar collisions may create middleweight black holes

Posted: Sun, Apr 18, 2004, 7:34 PM ET (2334 GMT)
Chandra image of M82 (Chandra X-Ray Obs.)

The collision of massive star may be the mechanism for creating "middleweight" black holes, which themselves may be the stepping stone towards creating even larger ones. Computer simulations published in the April 15 issue of the journal Nature show that collisions of giant stars, weighing on the order of one hundred times the mass of the Sun, can create massive bodies whose gravity can, in turn, attract other stars. The result is a "superstar" that, once it exhausts its supply of hydrogen fuel, collapses and forms a black hole. This mechanism could explain the existence of "middleweight" black holes that are larger than the stellar black holes formed in the collapse of somewhat smaller stars, but smaller than the supermassive black holes found in the center of galaxies, weighing several million solar masses. Whether middleweight black holes even exist at all has been a subject of debate, although new evidence from the Chandra X-Ray Observatory has turned up evidence for one in the galaxy M82.