<P> Binaries containing two neutron stars are observed to shrink as gravitational waves are emitted . Ultimately the neutron stars will come into contact and coalesce . The coalescence of binary neutron stars is one of the leading models for the origin of short gamma - ray bursts . Strong evidence for this model came from the observation of a kilonova associated with the short - duration gamma - ray burst GRB 130603B, and finally confirmed by detection of gravitational wave GW170817 and short GRB 170817A by LIGO, Virgo and 70 observatories covering the electromagnetic spectrum observed the event . The light emitted in the kilonova is believed to come from the radioactive decay of material ejected in the merger of the two neutron stars . This material may be responsible for the production of many of the chemical elements beyond iron, as opposed to the supernova nucleosynthesis theory . </P> <P> Neutron stars can host exoplanets . These can be original, circumbinary, captured, or the result of a second round of planet formation . Pulsars can also strip the atmosphere off from a star, leaving a planetary - mass remnant, which may be understood as a chthonian planet or a stellar object depending on interpretation . For pulsars, such pulsar planets can be detected with the pulsar timing method, which allows for high precision and detection of much smaller planets than with other methods . Two systems have been definitively confirmed . The first exoplanets ever to be detected were the three planets Draugr, Poltergeist and Phobetor around PSR B1257 + 12, discovered in 1992--1994 . Of these, Draugr is the smallest exoplanet ever detected, at a mass of twice that of the Moon . Another system is PSR B1620 - 26, where a circumbinary planet orbits a neutron star - white dwarf binary system . Also, there are several unconfirmed candidates . Pulsar planets receive little visible light, but massive amounts of ionizing radiation and high - energy stellar wind, which makes them rather hostile environments . </P> <P> In 1934, Walter Baade and Fritz Zwicky proposed the existence of neutron stars, only a year after the discovery of the neutron by Sir James Chadwick . In seeking an explanation for the origin of a supernova, they tentatively proposed that in supernova explosions ordinary stars are turned into stars that consist of extremely closely packed neutrons that they called neutron stars . Baade and Zwicky correctly proposed at that time that the release of the gravitational binding energy of the neutron stars powers the supernova: "In the supernova process, mass in bulk is annihilated". Neutron stars were thought to be too faint to be detectable and little work was done on them until November 1967, when Franco Pacini pointed out that if the neutron stars were spinning and had large magnetic fields, then electromagnetic waves would be emitted . Unbeknown to him, radio astronomer Antony Hewish and his research assistant Jocelyn Bell at Cambridge were shortly to detect radio pulses from stars that are now believed to be highly magnetized, rapidly spinning neutron stars, known as pulsars . </P> <P> In 1965, Antony Hewish and Samuel Okoye discovered "an unusual source of high radio brightness temperature in the Crab Nebula". This source turned out to be the Crab Pulsar that resulted from the great supernova of 1054 . </P>

A spinning neutron star that appears to give off radio waves is called a