Stellar Nucleosynthesis: Structures & Vocabulary

Stellar nucleosynthesis is the set of nuclear processes that build new atomic nuclei inside stars and during stellar explosions. Different temperature, density, neutron exposure, and evolutionary stages favor different reaction networks, so the periodic table records contributions from multiple astrophysical environments.

Fusion of light nuclei releases energy while product nuclei become more tightly bound up to the iron region. Beyond that region, fusion generally requires net energy, so heavy-element production depends strongly on neutron capture, radioactive decay, and explosive conditions rather than ordinary exothermic core fusion.

Stellar spectra reveal abundance patterns predicted by nuclear networks, meteorites contain isotopic signatures of different processes, supernova remnants show freshly synthesized elements, and observations of old stars preserve chemical fingerprints from earlier stellar generations.

Hydrogen burning creates helium; helium burning creates carbon and oxygen; massive stars add carbon, neon, oxygen, and silicon burning; neutron captures build many nuclei beyond iron; explosive burning and compact-object mergers add still other products.