Quark-nova
Encyclopedia
A quark-nova is a hypothetical type of supernova
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...

 that could occur if a neutron star
Neutron star
A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...

 spontaneously collapsed to become a quark star
Quark star
A quark star or strange star is a hypothetical type of exotic star composed of quark matter, or strange matter. These are ultra-dense phases of degenerate matter theorized to form inside particularly massive neutron stars....

. The concept of quark-novae was suggested by Dr. Rachid Ouyed (University of Calgary, Canada) and Drs. Dey and Dey (Calcutta University, India). The quark-nova hypothesis has been mentioned in various publications.

When a neutron star spins down, it could convert to a quark star through a process known as quark deconfinement. The resultant star would have quark matter in its interior. The process would release immense amounts of energy, perhaps explaining the most energetic explosions in the universe; rough calculations have estimated that as much as 1047 J could be released from the phase transition inside a neutron star. Quark-novae may be one cause of gamma ray bursts. According to Jaikumar et al., they may also be involved in producing heavy elements such as platinum through r-process nucleosynthesis
R-process
The r-process is a nucleosynthesis process, likely occurring in core-collapse supernovae responsible for the creation of approximately half of the neutron-rich atomic nuclei that are heavier than iron. The process entails a succession of rapid neutron captures on seed nuclei, typically Ni-56,...

.

Rapidly spinning neutron stars with masses between 1.5 and 1.8 solar masses are theoretically the best candidates for conversion due to spin down of the star within a Hubble time. This amounts to a small fraction of the projected neutron star population. A conservative estimate based on this indicates that up to two quark-novae may occur in the observable universe
Observable universe
In Big Bang cosmology, the observable universe consists of the galaxies and other matter that we can in principle observe from Earth in the present day, because light from those objects has had time to reach us since the beginning of the cosmological expansion...

 each day.

Theoretically quark stars would be radio-quiet, so radio-quiet neutron stars may be quark stars.

Direct evidence for quark-novae is scant; however recent observations of supernovae SN2006gy, SN2005gj and SN2005ap may point to their existence.

External links


See also

  • Quark matter
  • Quark-degenerate matter
  • Hypernova
    Hypernova
    Hypernova , also known as a type 1c Supernova, refers to an incredibly large star that collapses at the end of its lifespan...

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