The iron peak in nuclear binding energy

Assembled from 11 blocks · 2 evidence · 15 related

1. Story
2. Binding energy per nucleon rises steeply from hydrogen and peaks in the iron-nickel region, with iron-56 at roughly 8.79 MeV per nucleon and nickel-62 slightly higher still. Below the peak, fusing nuclei together releases energy; above it, fusion consumes energy. This single feature of the nuclear chart is what ends a massive star. As long as a core can fuse to a more tightly bound product it generates the pressure that holds the star up, but once the core is iron there is no exothermic reaction left, pressure support fails on a timescale of seconds, and the star collapses on itself. The peak is also why elements heavier than iron cannot be built by ordinary stellar burning and require neutron capture instead. Not a place.
3. Knowledge
4. The iron peak in nuclear binding energy
5. Connections
6. Supernova
7. Stellar nucleosynthesis
8. B2FH sets out the synthesis of the elements in stars
9. Evidence
10. Establishes stellar nucleosynthesis as the origin of the elements heavier than helium and organises production into distinct nuclear processes including slow and rapid neutron capture. Title, authors, journal, volume and pages were read from ADS and publisher listings via search; the review itself was not fetched, so the internal process taxonomy is described from secondary accounts.
11. Supports general stellar-physics statements in this pack: mass-luminosity scaling, main-sequence lifetimes, degeneracy support and the conventional 1.4 solar mass Chandrasekhar value. This is university-maintained educational reference material, not primary literature, and it was read via search summary rather than fetched. Primary citations should replace it for any figure a reader might quote.