| 单词 | neutron star |
| 释义 | neutron star A compact stellar object that is supported against collapse under self-gravity by the degeneracy pressure of the neutrons of which it is primarily composed. Neutron stars are believed to be formed as the end products of the evolution of stars of mass greater than a few (4–10) solar masses. The core of the evolved star collapses and (assuming that its mass is greater than the Chandrasekhar limit for a white dwarf), at the very high densities involved (about 1014 kg m-3), electrons react with protons in atomic nuclei to produce neutrons. The neutron-rich nuclei thus formed release free neutrons in a process known as neutron drip . The density increases to about 1017 kg m-3, at which most of the electrons and protons have been converted to a degenerate gas of neutrons and the atomic nuclei have lost their separate identities. If the mass of the core exceeds the Chandrasekhar limit for a neutron star, then further collapse will occur, leading to the formation of a black hole. Pulsars are believed to be rapidly rotating magnetized neutron stars and many X-ray sources are thought to be neutron stars in binary systems with another star, from which material is drawn into an accretion disc. This material, heated to a very high temperature, emits radiation in the X-ray region |
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