Knowra Degenerate matter Degenerate matter Matter at extremely high density whose pressure is governed chiefly by quantum-mechanical restrictions on how particles can occupy states. It occurs in compact stellar remnants such as white dwarfs and neutron stars.
Pauli exclusion principle : No two identical fermions can occupy the same quantum state simultaneously. It forces fermions into higher-momentum states as density rises, producing degeneracy pressure.
White dwarf : A compact stellar remnant supported mainly by electron degeneracy pressure. It is the clearest astronomical example of electron-degenerate matter.
Fermion : A particle with half-integer spin that obeys Fermi–Dirac statistics. Electrons and neutrons are fermions, so their state occupancy is restricted.
Ideal gas law : The relation between pressure, volume, temperature, and particle number for a classical ideal gas. Unlike a classical gas, degenerate matter can exert substantial pressure without high temperature.
Fermi energy : The energy of the highest occupied state in a system of fermions at zero temperature. It sets the characteristic energy scale of a densely packed degenerate fermion gas.
Chandrasekhar limit : The maximum mass, about 1.4 solar masses, for a cold, nonrotating white dwarf supported by electron degeneracy pressure. Above this limit, electron pressure cannot support a white dwarf against gravity.
Fermi–Dirac statistics : Quantum statistics describing the occupation of states by identical fermions. They predict how particles fill available energy states in degenerate matter.
Thermal pressure : Pressure produced by particles' random thermal motion. It decreases as matter cools, whereas degeneracy pressure remains at zero temperature.
Fermi gas : A collection of noninteracting fermions governed by Fermi–Dirac statistics. Its equation of state provides the basic model for idealized degenerate matter.
Neutron star : A compact stellar remnant composed predominantly of neutrons and other dense matter. Its interior may contain neutron-degenerate matter, with pressure modified by nuclear forces.
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