Characteristics
SN 2006gy occurred in a distant galaxy (NGC 1260), approximately 238 million light years (72 megaparsecs) away. Therefore, due to the time it took light from the supernova to reach Earth, the event occurred about 238 million years ago. Preliminary indications are that it was an unusually high-energy supernova of a very large star, around 150 solar masses (M⊙), possibly of a type referred to as a pair-instability supernova. The energy released by the explosion has been estimated at 1052 ergs (1045 J).
A pair instability supernova can only happen in stars that are very massive— having a range of around 130 to 250 solar masses. At a certain point in such a massive star's life its core begins to produce high energy gamma rays which have a greater energy than the rest mass of two electrons (mass-energy equivalence). These high energy gamma rays strike atomic nuclei and are converted from energy (or heat) to matter, disrupting the equilibrium between thermodynamic pressure and gravity in the star's core. The sudden drop in thermodynamic pressure causes the core to collapse. As the core collapses it gets hotter and hotter until a runaway thermonuclear reaction begins. In a few seconds, all of the fuel in the core undergoes a cataclysmic thermonuclear fusion, blowing the star completely apart while leaving nothing behind.
Although the SN 2006gy supernova was intrinsically about one hundred times as luminous as SN 1987A, which was bright enough to be seen by the naked eye, SN 2006gy was more than 1,400 times as far away as SN 1987A, and too far away to be seen without a telescope.
Denis Leahy and Rachid Ouyed, Canadian scientists from the University of Calgary have proposed that SN 2006gy was the birth of a quark star.
Another possibility is that SN 2006gy is not actually a pair-instability supernova but instead is powered by interaction with a dense circumstellar medium – a Type IIn supernova.
Read more about this topic: SN 2006gy