At the tender age of 9 million years, it has already started shutting down hydrogen fusion in its core, and sometime in the next million years it will blow itself apart in a
Type II supernova. Omicron Persei A is also a S1 giant, somewhat smaller than Zeta, but likewise fated to go out in a blaze of glory.
SN1987A was indeed fainter than a normal
type II supernova. The total energy released depends on the mass of the star, while the optical manifestation, which only accounts for about 0.01 per cent of the total energy, depends on the radius of the star.
SN 2005ap is classified as a
type II supernova, marking the collapse of a massive star.
(http://earthsky.org/astronomy-essentials/supernove-distance) EarthSky says there aren't any old, massive stars close enough to explode in a
Type II supernova, which happens when those huge stars collapse.
This
type II supernova has been given the interim designation J012634+3137036.
These isotopes could have come from a
Type II supernova, caused by the core-collapse of a massive star.
SN 2013df is classified as a (http://cse.ssl.berkeley.edu/bmendez/ay10/2000/cycle/snII.html)
Type II supernova .
NGC 5020 also played host to a
Type II supernova in 1991.
They conclude that the quantity of iron-60--especially in the 4- to 6-million-year-old middle layer--indicates a massive stellar explosion, probably a
type II supernova, about 5 million years ago.
During a
Type II supernova, the death of a massive but otherwise normal star, atoms are relentlessly bombarded with neutrons--more than a hundred billion trillion per cubic centimeter.
With a conservatively estimated peak luminosity of 50 billion Suns (absolute magnitude -22), Supernova 2006gy radiated about 100 times more energy than a typical
Type II supernova, which represents the death of a massive star.
If the star did explode as a normal
type II supernova, why then did it take up to four times as long to brighten and diminish as other such supernova and why did emit up to 100 times more X-rays energy than expected?
