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.
NGC 5020 also played host to a
Type II supernova in 1991.
SN1987A was indeed fainter than a normal
type II supernova.
SN 2005ap is classified as a
type II supernova, marking the collapse of a massive star.
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.
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.
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.
Due to an unfortunate alignment of circumstances, the supernova was erroneously classified by the astronomical community as a common
Type II supernova and filed away.
Shock waves and neutrinos propagate out from the core to rip apart the star's outer layers and fling them into space, producing the energetic blast we witness as a Type Ib, Type Ic, or
Type II supernova.
That makes it a candidate to one day explode as a
Type II supernova, an event that could occur tomorrow or anytime in the next million years.
