It has been suggested that this article or section be merged into Compact star. (Discuss)

A degenerate star is type of star which is composed of degenerate matter. It is the generic name of three types of stars, degenerate dwarf (commonly called white dwarf), neutron star and quark star. The first two have been conclusively observed to exist in nature, while the latter may be represented in RX J1856.5-3754 and 3C58, though observations are inconclusive. Wikipedia does not have an article with this exact name. ... It has been suggested that Degenerate star be merged into this article or section. ... The Pleiades, an open cluster of stars in the constellation of Taurus. ... Degenerate matter is matter which has sufficiently high density that the dominant contribution to its pressure arises from the Pauli exclusion principle. ... A Degenerate dwarf is type of star, an alternative name for what is commonly called a White dwarf (see this reference for a more complete article). ... Image of Sirius A and Sirius B taken by the Hubble Space Telescope. ... A neutron star is one of the few possible endpoints of stellar evolution. ... A strange star or quark star is a hypothetical type of star composed of strange matter, or quark matter. ... RX J1856. ... an X-Ray image of 3C58 from the orbiting Chandra X-Ray Observatory. ...

In general in a star the gravitational pull of matter tends to squeeze the star to smaller size, but most stars are in a state of static equilibrium (where gravity is exactly counterbalanced by other forces) and they remain a constant size.

In general, in main sequence stars (our Sun is a main sequence star), gravitational pressure is counterbalanced by the thermal motion of the star's atoms. Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ...

A star which is gravitationally compacted to a greater density than that of a degenerate star is a stellar mass black hole A stellar black hole is a black hole formed by the gravitational collapse of a massive star (3 or more solar masses) at the end of its lifetime. ...

White Dwarfs

If the gravitational pressure is strong enough to overcome thermal motion, as for example when fusion slows or ceases from lack of fuel, the next potential equilibrium state is due to electron degeneracy pressure. The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ...

A star like this is composed of electron degenerate matter, supported against gravity only by the resistance of electrons to being squeezed into the same energy state around the nucleus (as described by the Pauli exclusion principle). The Pauli exclusion principle is a quantum mechanical principle formulated by Wolfgang Pauli in 1925, which states that no two identical fermions may occupy the same quantum state simultaneously. ...

Such a star is called a degenerate dwarf, or more commonly a white dwarf. A cold white dwarf is known as the theoretical black dwarf. They were observed for the first time in the 19th century, but the extremely high densities and pressures were not explained until 1932. A Degenerate dwarf is type of star, an alternative name for what is commonly called a White dwarf (see this reference for a more complete article). ... Image of Sirius A and Sirius B taken by the Hubble Space Telescope. ... A black dwarf is a hypothetical astronomical object: a white dwarf so old that it has cooled down so that it no longer emits significant heat or light. ...

Neutron Stars

If the gravitational pressure is still larger, electrons are forced into the nucleii where they merge with protons, creating baryon degenerate matter. The entire star becomes a homogenous lump of neutrons, and is called a neutron star. A neutron star is one of the few possible endpoints of stellar evolution. ...

The existence of neutron stars was predicted on theoretical grounds in 1933 as a possible state of a large number of neutrons, amounting to about the mass of the Sun. In 1963 neutron stars were for the first time observed as radio pulsar, later also as stellar x-ray source. Composite Optical/X-ray image of the Crab Nebula pulsar, showing surrounding nebular gases stirred by the pulsars magnetic field and radiation. ...

Quark Stars

In theory, if gravitational pressure is even stronger, the matter in the star may be reduced to a soup of quarks, called a quark star or less generally a strange star. There have not yet been any confirmed observations of quark stars. The interior of the star would be akin to a giant nucleon. A strange star or quark star is a hypothetical type of star composed of strange matter, or quark matter. ... A strange star or quark star is a hypothetical type of star composed of strange matter. ... In physics a nucleon is a collective name for two baryons: the neutron and the proton. ...

Preon Stars

Hypothetically, if gravitational pressure were stronger, stellar matter would be reduced to quark constituents, preons or sub-quarks. The preon star would then be a giant quark. The basis of sub-quarks in theory is not generally accepted. Preons do not exist as part of the Standard Model of quantum physics. In particle physics, preons are postulated point-like particles, conceived to be subcomponents of quarks and leptons. ... A preon star is a hypothetical compact star made of preons, a group of theoretical subatomic particles that may compose quarks and leptons. ... These are the 6 quarks and their most likely decay modes. ...