degenerate matter


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Related to degenerate matter: Quark gluon plasma

degenerate matter

Matter in a highly dense form that can exert a pressure as a result of quantum mechanical effects. Degenerate matter occurs in white dwarfs and neutron stars. During the gravitational collapse of a dying star, the electrons are stripped from their atomic nuclei, and nuclei and electrons exist in a closely packed, highly dense mass. As the density increases, the number of electrons per unit volume increases to a point when the electrons can exert a considerable pressure, called degeneracy pressure. This pressure is a result of the laws of quantum mechanics. Unlike normal pressure, degeneracy pressure is essentially independent of temperature, depending primarily on density. At the immense densities typical of white dwarfs (107 kg m–3 or more) it becomes sufficiently large to counteract the gravitational force and thus prevents the star from collapsing further. The gross properties of a white dwarf are therefore described in terms of a gas of degenerate electrons.

Above a certain stellar mass (the Chandrasekhar limit) equilibrium cannot be attained by a balance of gravitational force and electron degeneracy pressure. The star must collapse further to become a neutron star. It is then the degeneracy pressure exerted by the tightly packed neutrons that balances the gravitational force. See also black hole.

degenerate matter

[di′jen·ə·rət ′mad·ər]
(physics)
Matter that has been stripped of its orbital electrons, so the nuclei are packed close together.
References in periodicals archive ?
These supernovas can leave behind a rapidly spinning neutron star (pulsar), composed primarily of neutron degenerate matter, which keeps this bizarre object bouncy against crushing gravity.
This material is, of course, termed quark degenerate matter, and it keeps what is left of what once was a very massive star bouncy despite a heartless crush.
The application of fully degenerate matter to the large planets and the white dwarfs was an unusual concept in light of a fully gaseous Sun.
The generation of a thermal spectrum with a blackbody lineshape has been solely a quality of condensed matter, not of gases, degenerate matter, or any other state which physicists might create.
But degenerate matter has an Achilles' heel: destroy the electrons and the star's supporting pressure vanishes.