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Hi all, this is amazing.
we have been advised from Chile that it is likely this object is a "super-Chandra" SN Ia, reminiscent of SN 2006gz, 2007if, 2009dc.
I researched "Super-Chandra", and have extracted some info below.
If it is a Super Chandra, it looks to me like Stu has stumbled upon a very rare object indeed, which is still quite a mystery.
A type 1a supernova is normally a white dwarf star less than 1.4 solar masses, and is part of a binary system. In this case however, was it an explosion of a single white dwarf of mass greater than the Chandra limit of 1.4 solar masses in a binary system, or a merger of 2 white dwarves, or something else?
I would imagine that this discovery should generate a lot of interest and intense observing time to try to add to the missing body of knowledge here?
At this stage, it is still early days, so things could change, but we'll keep you posted!
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From wikepedia:
In April 2003, the Supernova Legacy Survey observed a type Ia supernova, designated SNLS-03D3bb, in a galaxy approximately 4 billion light years away. According to a group of astronomers at the University of Toronto and elsewhere, the observations of this supernova are best explained by assuming that it arose from a white dwarf which grew to twice the mass of the Sun before exploding. They believe that the star, dubbed the "Champagne Supernova" by University of Oklahoma astronomer David R. Branch, may have been spinning so fast that centrifugal force allowed it to exceed the limit. Alternatively, the supernova may have resulted from the merger of two white dwarfs, so that the limit was only violated momentarily.
From Yale News, March 15 2010:
Since 2003, four supernovae have been discovered that were so bright, cosmologists wondered whether their white dwarfs had surpassed the Chandrasekhar limit. These supernovae have been dubbed the “super-Chandrasekhar” supernovae.
Now Richard Scalzo of Yale, as part of a collaboration of American and French physicists called the Nearby Supernova Factory, has measured the mass of the white dwarf star that resulted in one of these rare supernovae, called SN 2007if, and confirmed that it exceeded the Chandrasekhar limit. They also discovered that the unusually bright supernova had not only a central mass, but a shell of material that was ejected during the explosion as well as a surrounding envelope of pre-existing material. The team hopes this discovery will provide a structural model with which to understand the other supermassive supernovae.
Using observations from telescopes in Chile, Hawaii and California, the team was able to measure the mass of the central star, the shell and the envelope individually, providing the first conclusive evidence that the star system itself did indeed surpass the Chandrasekhar limit. They found that the star itself appears to have had a mass of 2.1 times the mass of the Sun (plus or minus 10 percent), putting it well above the limit.
Being able to measure masses for all parts of the star system tells the physicists about how the system may have evolved—a process that is currently poorly understood. “We don’t really know much about the stars that lead to these supernovae,” Scalzo said. “We want to know more about what kind of stars they were, and how they formed and evolved over time.
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