Search results
Results from the WOW.Com Content Network
This is the pressure that prevents a white dwarf star from collapsing. A star exceeding this limit and without significant thermally generated pressure will continue to collapse to form either a neutron star or black hole, because the degeneracy pressure provided by the electrons is weaker than the inward pull of gravity.
While degeneracy pressure usually dominates at extremely high densities, it is the ratio between degenerate pressure and thermal pressure which determines degeneracy. Given a sufficiently drastic increase in temperature (such as during a red giant star's helium flash ), matter can become non-degenerate without reducing its density.
This pressure is known as the degeneracy pressure. In this sense, systems composed of fermions are also referred as degenerate matter . Standard stars avoid collapse by balancing thermal pressure ( plasma and radiation) against gravitational forces.
Quantum-mechanical electron degeneracy pressure in a block of copper [83] 48 GPa Detonation pressure of pure CL-20, [84] the most powerful high explosive in mass production 69 GPa 10,000,000 psi Highest water jet pressure attained in research lab [85] 96 GPa Pressure at which metallic oxygen forms (960,000 bar) [81] 10 11 Pa
Conversely, two or more different states of a quantum mechanical system are said to be degenerate if they give the same value of energy upon measurement. The number of different states corresponding to a particular energy level is known as the degree of degeneracy (or simply the degeneracy) of the level.
The Chandrasekhar limit is a consequence of competition between gravity and electron degeneracy pressure. Electron degeneracy pressure is a quantum-mechanical effect arising from the Pauli exclusion principle. Since electrons are fermions, no two electrons can be in the same state, so not all electrons can be in the minimum-energy level.
Some massive stars collapse to form neutron stars at the end of their life cycle, as has been both observed and explained theoretically.Under the extreme temperatures and pressures inside neutron stars, the neutrons are normally kept apart by a degeneracy pressure, stabilizing the star and hindering further gravitational collapse. [2]
This pressure is called the electron degeneracy pressure and does not come from repulsion or motion of the electrons but from the restriction that no more than two electrons (due to the two values of spin) can occupy the same energy level. This pressure defines the compressibility or bulk modulus of the metal [Ashcroft & Mermin 8]