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Stellar nucleosynthesis
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Stars forge elements up to iron.
Stars fuse elements: H → He, He → C, O, then Ne, Mg, Si up to iron; heavier elements come from neutron capture in supernovae and neutron-star mergers. 'We are stardust'.
Gold forms in neutron-star collisions.
Iron fusion doesn't release energy.
In more detail
Stellar nucleosynthesis creates heavier elements in stars through fusion, with iron forming in massive stars. Heavier elements beyond iron are created in supernovae and neutron star mergers.
Real-world uses
- Stellar nucleosynthesis explains the abundance of elements in the Solar System.
- Spectroscopy of stars reveals their chemical composition.
- Physicists explain how the carbon, oxygen and iron in our bodies and planets were made inside stars.
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Frequently asked questions
Where does carbon come from?
Mainly from helium fusion in stars, which produces carbon and oxygen.
Where does gold come from?
Mostly from neutron star mergers and some supernovae.
Why does fusion stop at iron?
Iron has the highest binding energy per nucleon, so fusing iron absorbs rather than releases energy.
Related topics in Particle Physics & Cosmology
Our Sun · Stellar life cycle · Hertzsprung–Russell diagram · Supernovae · White dwarfs · Chandrasekhar limit