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Interest in quark nova theory growing

Hypothesis helps explain mysterious observations in Cassiopeia supernova
April 10, 2014

Research by Rachid Ouyed at the Quark Nova Project has been featured recently in Nature, New Scientist and National Geographic. Photo courtesy Rachid Ouyed

Composite image shows the Cassiopeia A supernova remnant across the spectrum: Gamma rays (magenta) from NASA's Fermi Gamma-ray Space Telescope; X-rays (blue, green) from NASA's Chandra X-ray Observatory; visible light (yellow) from the Hubble Space Telescope; infrared (red) from NASA's Spitzer Space Telescope; and radio (orange) from the Very Large Array near Socorro, New Mexico. Composite illustration by NASA/DOE/Fermi LAT Collaboration, CXC/SAO/JPL-Caltech/Steward/O. Krause et al., and NRAO/AUI. CC By 2.0

Composite image shows the Cassiopeia A supernova remnant across the spectrum: Gamma rays (magenta) from NASA's Fermi Gamma-ray Space Telescope; X-rays (blue, green) from NASA's Chandra X-ray Observatory; visible light (yellow) from the Hubble Space Telescope; infrared (red) from NASA's Spitzer Space Telescope; and radio (orange) from the Very Large Array near Socorro, New Mexico. Composite illustration by NASA/DOE/Fermi LAT Collaboration, CXC/SAO/JPL-Caltech/Steward/O. Krause et al., and NRAO/AUI. CC By 2.0

After more than a decade of research into the quark nova – a violent, hypothesized explosion that happens after a neutron star converts to quark matter, generating immense amounts of energy – the theory is getting a lot of attention in prestigious journals.

For years, Rachid Ouyed, the head of the Quark Nova Project at the University of Calgary, has theorized that when a star explodes in a supernova, the compact remnant of the explosion, called a neutron star, eventually explodes in a quark nova, another massive explosion that happens days to months after the first explosion.

“When people talk about a supernova, they think of one explosion and we have been saying, ‘Wait a second, there are situations where the neutron star itself can explode,’” says Ouyed, professor in the Department of Physics and Astronomy. 

“Inside the neutron star, the densities are so high, the matter turns into quarks, eventually forming a quark star that is so explosive that it shines much brighter than a supernova. It’s a very simple step that we took and now astronomers and physicists are thinking: ‘OK that makes sense.’”

In the last couple of years, astronomers have observed two supernovae that have appeared to explode twice – which is impossible, until you consider the second explosion as a quark nova. “Recently, when astronomers looked at the supernova in Cassiopeia they saw strange things that only make sense in the context of a quark nova,” says Ouyed. “Basically, we have done the work numerically, analytically and now observationally. We're actually finding some signatures for the quark nova. It’s very exciting!”

The astrophysics community is taking a lot of notice. National Geographic, Nature and New Scientist have all written about the Quark Nova Project in recent months. “The fact that it's gaining interest in these journals means we are doing something right,” says Ouyed.

The existence of quark novae would help scientists understand how matter behaves at extremely high densities and explain the distribution of some nuclear elements and the existence of others.

“We have put a lot of effort into making viable predictions so they can be tested. You can’t make such huge claims without some sort of observational support,” says Ouyed.  “We are being noticed slowly and one thing the community realizes now is that’s it’s not such a crazy idea.”