LIGO-Virgo finds mystery object in ’mass gap’
An unusual gravitational wave signal is casting new light on the 'mass gap' between neutron stars and black holes. When the most massive stars die, they collapse under their own gravity and leave behind black holes. When stars that are a bit less massive than this die, they explode in a supernova and leave behind dense, dead remnants of stars called neutron stars. For decades, astronomers have been puzzled by a gap that lies between neutron stars and black holes. The heaviest known neutron star is no more than 2.5 times the mass of our sun, or 2.5 solar masses, and the lightest known black hole is about 5 solar masses. On August 14 last year, the National Science Foundation's Laser Interferometer Gravitational-Wave Observatory (LIGO), based in the USA, and the European Virgo detector picked up a gravitational wave signal from the merger of two astronomical objects which could help develop scientists' understanding of the mass gap. A paper about the detection is published today in The Astrophysical Journal Letters.
