Astronomers have found a stellar-mass black hole bigger than what current models of stellar evolution deem possible. 70 times the mass of the Sun, LB-1 has left astronomers at a loss to explain how a black hole that size should come to exist in the Milky Way.
“LB-1 is twice as massive as what we thought possible. Now theorists will have to take up the challenge of explaining its formation,” said astronomer Jifeng Liu of the National Astronomical Observatory of China.
According to Science Alert, there are two theories about how black holes are formed. A stellar black hole is up to 20 times the mass of the Sun which forms when the centre of a star collapses in on itself. Supermassive black holes, which are millions times bigger than the Sun and their origins are have not been definitively determined.
But LB-1 doesn’t fall into either of these categories. Speculative theories about how it was formed are that it is the result of a collision between two black holes or it could be a fallback supernova. However, both these theories have little evidence and certain issues which make these LB-1 fall outside of these theories. This is making scientists believe there is another way black holes can form that hasn’t been identified yet.
“This discovery forces us to re-examine our models of how stellar-mass black holes form,” LIGO Director David Reitze of the University of Florida, who was not involved in the research told Science Alert.
The research has been published in Nature.