<P> A neutron star is the collapsed core of a large star which before collapse had a total of between 10 and 29 solar masses . Neutron stars are the smallest and densest stars known to exist . Though neutron stars typically have a radius on the order of 10 kilometres ( 6.2 mi ) , they can have masses of about twice that of the Sun . They result from the supernova explosion of a massive star , combined with gravitational collapse , that compresses the core past the white dwarf star density to that of atomic nuclei . Once formed , they no longer actively generate heat and cool over time ; however , they may still evolve further through collision or accretion . Most of the basic models for these objects imply that neutron stars are composed almost entirely of neutrons , which are subatomic particles with no net electrical charge and with slightly larger mass than protons . Neutron stars are supported against further collapse by neutron degeneracy pressure , a phenomenon described by the Pauli exclusion principle , just as white dwarfs are supported against collapse by electron degeneracy pressure . If the remnant star has a mass greater than about 3 solar masses , it continues collapsing to form a black hole . </P>
<P> A neutron star is the collapsed core of a large star which before collapse had a total of between 10 and 29 solar masses . Neutron stars are the smallest and densest stars known to exist . Though neutron stars typically have a radius on the order of 10 kilometres ( 6.2 mi ) , they can have masses of about twice that of the Sun . They result from the supernova explosion of a massive star , combined with gravitational collapse , that compresses the core past the white dwarf star density to that of atomic nuclei . Once formed , they no longer actively generate heat and cool over time ; however , they may still evolve further through collision or accretion . Most of the basic models for these objects imply that neutron stars are composed almost entirely of neutrons , which are subatomic particles with no net electrical charge and with slightly larger mass than protons . Neutron stars are supported against further collapse by neutron degeneracy pressure , a phenomenon described by the Pauli exclusion principle , just as white dwarfs are supported against collapse by electron degeneracy pressure . If the remnant star has a mass greater than about 3 solar masses , it continues collapsing to form a black hole . </P>
what are the densest stars known to exist
what are the densest stars known to exist
Neutron stars
Neutron stars