Astronomy & Celestial Mechanics
the sky, computed
Generator

The binding-energy generator

Binding energy per nucleon
Binding energy per nucleon. Binding energy per nucleon against mass number, from measured nuclide masses. The maximum is at Ni-62 at 8.795 MeV, so fusion releases energy up to that point and costs energy beyond it — which is the reason a star's core cannot burn its way past iron and nickel.

Binding energy per nucleon against mass number, from measured nuclide masses. The maximum is at Ni-62 at 8.795 MeV, so fusion releases energy up to that point and costs energy beyond it — which is the reason a star's core cannot burn its way past iron and nickel.

1 essay calls binding-energy. The drawing above is what it returns with no arguments at all; every call below passes it something, because a placement that passes nothing draws whichever member of the family the generator happens to default to rather than the one its essay argues about.

Where it is called

Every figure listed here is the same construction drawn at different numbers, so a correction to one is a correction to all of them.

Energy generation against core temperature. The proton–proton chain and the CNO cycle, in solar units, against core temperature on logarithmic axes. The CNO curve is far steeper, so the two cross at 18.8 million kelvin — above that temperature a star runs mostly on CNO, and below it mostly on pp. Stars

The furnace that runs cooler than a compost heap

The Sun's core produces 276 watts per cubic metre. A human body produces more. The Sun is bright because it is enormous, and its fusion is astonishingly slow — which is exactly why it lasts.

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