Why does the formation of an iron core lead to catastrophic collapse in massive stars?

Answer

Iron fusion consumes energy rather than producing it, removing the outward energy source.

Once iron forms in the core, nuclear fusion stops being an energy source; instead, iron fusion consumes energy. This instantly eliminates the outward pressure supporting the star, allowing gravity to cause catastrophic collapse.

Why does the formation of an iron core lead to catastrophic collapse in massive stars?
instabilitystar