A quark-nova is the
hypothetical violent explosion resulting from the conversion of a
neutron star
A neutron star is the gravitationally collapsed Stellar core, core of a massive supergiant star. It results from the supernova explosion of a stellar evolution#Massive star, massive star—combined with gravitational collapse—that compresses ...
to a
quark star. Analogous to a
supernova
A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...
heralding the birth of a neutron star, a quark nova signals the creation of a quark star. The term quark-novae was coined in 2002 by Dr. Rachid Ouyed (currently at the
University of Calgary
{{Infobox university
, name = University of Calgary
, image = University of Calgary coat of arms without motto scroll.svg
, image_size = 150px
, caption = Coat of arms
, former ...
, Canada) and Drs. J. Dey and M. Dey (Calcutta University, India).
The nova process
When a neutron star spins down, it may 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; calculations have estimated that as much as 10
46 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 and collaborators, they may also be involved in producing heavy elements such as
platinum
Platinum is a chemical element; it has Symbol (chemistry), symbol Pt and atomic number 78. It is a density, dense, malleable, ductility, ductile, highly unreactive, precious metal, precious, silverish-white transition metal. Its name origina ...
through
r-process nucleosynthesis.
Candidates
Rapidly spinning neutron stars with masses between 1.5 and 1.8
solar mass
The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxie ...
es are hypothetically 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
The observable universe is a Ball (mathematics), spherical region of the universe consisting of all matter that can be observation, observed from Earth; the electromagnetic radiation from these astronomical object, objects has had time to reach t ...
each day.
Hypothetically, quark stars would be radio-quiet, so
radio-quiet neutron stars may be quark stars.
Observations
Direct evidence for quark-novae is scant; however, recent observations of supernovae
SN 2006gy,
SN 2005gj and
SN 2005ap may point to their existence.
See also
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References
External links
Quark-novae produce neutrino bursts, which can be detected by neutrino observatories
(SpaceDaily) June 7, 2006
Quark Nova Project animations
(University of Calgary)
{{DEFAULTSORT:Quark-Nova
Quark stars
Supernovae
Hypothetical astronomical objects