How stars forge elements from hydrogen to iron through successive fusion stages
Burning Stages
T ≈ 1.5 × 10⁷ K
T ≈ 10⁸ K
T ≈ 5 × 10⁸ K
T ≈ 10⁹ K
T ≈ 3 × 10⁹ K
T ≈ 10¹⁰ K → collapse
Stellar Nucleosynthesis is how stars build heavy elements from hydrogen. Each stage requires higher temperatures as the Coulomb barrier grows with nuclear charge. The chain ends at iron (Fe-56) — the most stable nucleus — beyond which fusion absorbs rather than releases energy. Heavier elements are forged in supernova explosions via rapid neutron capture (r-process). As Sagan said: "We are made of star stuff."