Quark star free#

near zero external pressure and temperature). This kind of quark matter is known specifically as strange quark matter and it is speculated and subject to current scientific investigation whether it might in fact be stable under the conditions of interstellar space (i.e. It has been shown that the high Fermi energy making ordinary quark matter unstable at low temperatures and pressures can be lowered substantially by the transformation of a sufficient number of up and down quarks into strange quarks, as strange quarks are, relatively speaking, a very heavy type of quark particle. This suggests that the only stable quark stars will be neutron stars with a quark matter core, while quark stars consisting entirely of ordinary quark matter will be highly unstable and dissolve spontaneously. Ordinary quark matter consisting of up and down quarks (also referred to as u and d quarks) has a very high Fermi energy compared to ordinary atomic matter and is stable only under extreme temperatures and/or pressures. This conversion might be confined to the neutron star's center or it might transform the entire star, depending on the physical circumstances. It is theorized that when the neutron-degenerate matter, which makes up neutron stars, is put under sufficient pressure from the star's own gravity or the initial supernova creating it, the individual neutrons break down into their constituent quarks ( up quarks and down quarks), forming what is known as quark matter. TOV solution neutron quark star mass radius diagram The theory predicts quark matter to possess some peculiar characteristics under these conditions. The conditions inside compact stars with extremely high densities and temperatures well below 10 12 K cannot be recreated artificially, as there are no known methods to produce, store or study 'cold' quark matter directly as it would be found inside quark stars. Experimentally, the behaviour of quark matter is being actively studied with particle colliders, but this can only produce very hot (above 10 12 K) quarkвЂ“gluon plasma blobs the size of atomic nuclei, which decay immediately after formation. Theoretical uncertainties have precluded making predictions from first principles. The equation of state of quark matter is uncertain, as is the transition point between neutron-degenerate matter and quark matter.

The analysis about quark stars was first proposed in 1965 by Soviet physicists D. For example, they might be radio-silent, or have atypical sizes, electromagnetic fields, or surface temperatures, compared to neutron stars.

Quark star free#

They would also lack some features of neutron stars, unless they also contained a shell of neutron matter, because free quarks are not expected to have properties matching degenerate neutron matter.

If they exist, quark stars would resemble and be easily mistaken for neutron stars: they would form in the death of a massive star in a Type II supernova, be extremely dense and small, and possess a very high gravitational field. They could also form if a massive star collapses at the end of its life, provided that it is possible for a star to be large enough to collapse beyond a neutron star but not large enough to form a black hole. If quark stars can form, then the most likely place to find quark star matter would be inside neutron stars that exceed the internal pressure needed for quark degeneracy вЂ“ the point at which neutrons break down into a form of dense quark matter. The stability of quark matter, and hence the existence of quark stars, is for these reasons among the unsolved problems in physics. Theoretically, such a scenario is seen as scientifically plausible, but it has been impossible to prove both observationally and experimentally, because the very extreme conditions needed for stabilizing quark matter cannot be created in any laboratory nor observed directly in nature. If these ideas are correct, quark stars might occur, and be observable, somewhere in the universe. In this state, a new equilibrium is supposed to emerge, as a new degeneracy pressure between the quarks, as well as repulsive electromagnetic forces, will occur and hinder total gravitational collapse. However, it is hypothesized that under even more extreme temperature and pressure, the degeneracy pressure of the neutrons is overcome, and the neutrons are forced to merge and dissolve into their constituent quarks, creating an ultra-dense phase of quark matter based on densely packed quarks.

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. Some massive stars collapse to form neutron stars at the end of their life cycle, as has been both observed and explained theoretically.