A1 Supernovas: Star Collapse and Explosion

Topic

The central figure in this model is the star—or, in an alternative scenario, the white dwarf—which eventually crosses a mass threshold it can no longer support; beyond this point, there are two completely different paths that nonetheless lead to the same catastrophic outcome.

In the first scenario, the iron core of a very massive star grows until it exceeds the mass limit that the core's degeneracy pressure can sustain; crossing this limit causes the core to collapse in on itself in a fraction of a second. The rebound from this collapse generates a shock wave that violently ejects the star's outer layers, releasing a tremendous amount of energy—the vast majority of which escapes as neutrinos, while only a small fraction is released as the light we actually see shining as a supernova.

In the second scenario, a white dwarf within a binary system accumulates matter from its companion star until it nears its own mass limit—the limit supported by electron degeneracy pressure within the white dwarf. Approaching this limit triggers a runaway thermonuclear fusion reaction inside the white dwarf, ultimately destroying it completely and leaving no remnant behind.

In both scenarios, the burst of neutrinos accompanying the collapse can be detected on Earth even before the visible light from the event arrives—as has already occurred with a nearby supernova observed in the past. Thus, from the crossing of the mass threshold that marks the beginning of this document to the early neutrino detection that concludes it—and encompassing both the iron core collapse and the runaway thermonuclear fusion of the white dwarf—the star and the white dwarf in this model demonstrate that crossing an unsustainable mass limit spells the definitive end of the star's life, regardless of which of the two paths is taken.

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