Neutron Stars: How their merging creates gamma-ray bursts and contributes to the creation of heavy elements in the universe.

Friday - May 5 2023, 13:56 UTC - 1 year ago

Neutron stars are incredibly dense stars resulting from the gravitational collapse of a massive star after a supernova explosion. They have been observed to have powerful gravitational and magnetic fields, and to rotate rapidly. Scientists thought there were two varieties of Gamma-Ray Bursts (GRBs) -- long bursts associated with black holes and short bursts associated with neutron star mergers -- until a December 11, 2021 discovery showed that long bursts could also be caused by neutron star mergers. This necessitates incorporating long burst GRBs into heavy element production estimates, as they now make up an inherent part of the process of neutron star merging.

Neutron stars are incredibly dense stars created from the gravitational collapse of a massive star after a supernova explosion. This collapse forces the protons and electrons to combine into neutrons, and neutron stars have been observed to have a mass of about 1.4 to 3 times that of the sun but compressed into a sphere with a diameter of only about 20 kilometers. This makes them incredibly dense, and a sugar-cube-sized amount of neutron-star material would weigh about as much as a mountain. Despite their small size, they have powerful gravitational and magnetic fields, and rotate rapidly, with some spinning hundreds of times per second.

Neutron stars are known to occasionally merge and emit powerful gamma-ray blasts known as Gamma-Ray Bursts (GRBs). Scientists think these powerful events, which can be observed across great distances in the universe, are factories for a significant portion of the universe’s heavy elements, including gold. But until 2021, GRBs were thought to be of two varieties: long bursts with a duration of two seconds or more, associated with black hole formation, and short bursts with a duration of less than two seconds, believed to be caused by mergers of neutron stars.

A December 11, 2021 discovery modified those theories, showing that long bursts associated with black hole formation can also be caused by neutron stars merging. This necessitates incorporating long burst GRBs into heavy element production estimates, as they now make up an inherent part of the merging of neutron stars. This discovery is a further step in our understanding of how heavy elements are produced in the universe.

The merging of neutron stars is also crucial in astrobiology, as it is one of the few known sources of gamma ray bursts, which is seen as a potential sign of life in the universe.