Shortly after the discovery of neutrons by Chadwick in 1932, the Soviet physicist Landau proposed that a class of stars could all be composed of neutrons, making Landau the first scholar to propose the concept of neutron stars.

 In 1934, Bud and Zweiki published an article in Physical Review, believing that supernova explosion can transform an ordinary star into a neutron star, and pointing out that this process can accelerate particles and produce cosmic rays.

Oppenheimer and Volkow established the first quantitative neutron star model by calculation in 1939, but their equation of state is an ideal degenerate neutron gas model. Neutron stars are stars in the late stage of evolution, which are also formed in the center of old stars.

 It's just that the stars that can form neutron stars are more massive. According to scientists' calculations, when the mass of an old star is greater than the mass of ten suns, it may eventually become a neutron star, while a star with a mass of less than eight suns can only become a white dwarf star