After the material in the core of a massive star has been converted to iron by thermonuclear reactions, further energy can be released to heat the core only by

Question

Quizplus · Accepted Answer

Gravitational contraction is the only process listed that can release further energy after a massive star's core has been converted to iron. This is because iron is the end point of energy-generating nuclear fusion in stars; fusing iron or heavier elements consumes energy rather than releases it, and nuclear fission and the absorption of neutrinos do not play a role in heating the core at this stage.

After the Material in the Core of a Massive Star