New Delhi: Scientists have spotted a black hole triple system at a distance of 8,000 lightyears. The central black hole is designated as V404 Cygni, which is feeding on the outer atmosphere of a nearby star, and is orbited by a second, even more distant star. This is the first black hole system discovered. Scientists have previously discovered stellar mass black holes with binary companions, which may be stars or much denser remnants of dead stars, including neutron stars or other black holes. However, astronomers have not yet discovered a black hole with two companions so far.
A small star is orbiting the central black hole every 6.5 days, which is a similar configuration to most binary systems. The surprising aspect of the system is a distant companion that is orbiting the black hole every 70,000 years. Black holes are formed by the violent deaths of massive stars, that can no longer sustain nuclear fusion and collapse under the influence of their own gravity. Such a supernova eruption should have ejected any distant companion stars in the system. The fact that the third star continues to orbit the black hole may for the first time indicate a method for black hole formation that has only been proposed in theory.
A ‘gentle’ black hole formation
Instead of the birth of the black hole being marked by the violent death of a massive star, it is possible for the black hole to directly collapse from a dense cloud of gas and dust, the material from which new stars are born. A paper describing the findings has been published in Nature. One of the authors of the study, Kevin Burdge says, “We think most black holes form from violent explosions of stars, but this discovery helps call that into question. This system is super exciting for black hole evolution, and it also raises questions of whether there are more triples out there.” If the black hole indeed formed from a direct collapse, it was born around four billion years ago.
