- Class O (blue supergiant) stars that have reached their maximum mass, and as a result, the magnetic ionization level of the star becomes sufficient to cause age-limit detonation at the Nickel-Iron-Cobalt layer within the star, causing a supernova. These are the Type II supernovae of conventional astronomy.
- A later-generation star. These supernova reconstructed stars start with a high concentration of heavy elements, already near their age limit and may become a supernova in any stellar class. These are the Type I supernovae.
The primary factor in the evolutionary speed of a star is the amount of matter available for it to consume. The more matter, the faster it will grow. As a result, stars present in nebula and dust clouds quickly move to the blue giant range and become supernovae. The most common example of this is when a globular cluster becomes trapped in the dust-filled galactic disk, becoming an open cluster. Red, globular clusters predominate outside the galactic disk and blue, open clusters predominate inside because of the availability of dust. Supernovae in red, globular clusters will be rare. Supernovae in the galactic disk will be common, and in the galactic core where there is a considerable quantity of heavy elements, very common (though not easily observed).