nucleoszintézis

Nucleosynthesis refers to the process by which new atomic nuclei are created from pre-existing nucleons (protons and neutrons). This cosmic phenomenon is responsible for the formation of all the chemical elements heavier than hydrogen and helium. The primary site of nucleosynthesis in the universe is within stars.

During the main sequence phase of a star's life, nuclear fusion within its core converts hydrogen into helium. As stars evolve and their core conditions change, they can fuse helium into heavier elements like carbon, oxygen, and neon. More massive stars, through processes like the CNO cycle and the triple-alpha process, can synthesize elements up to iron.

The creation of elements heavier than iron occurs primarily through neutron capture processes. In the s-process (slow neutron capture), nuclei gradually absorb neutrons over long timescales, leading to the formation of heavier elements. The r-process (rapid neutron capture) involves a much faster rate of neutron capture, typically occurring during catastrophic stellar events like supernovae or neutron star mergers, and is responsible for producing the heaviest naturally occurring elements.

The Big Bang itself also played a crucial role in nucleosynthesis, producing the initial light elements: hydrogen, helium, and lithium. This primordial nucleosynthesis occurred in the first few minutes after the Big Bang, establishing the baseline composition of the early universe. Subsequent stellar nucleosynthesis and explosive events have enriched the cosmos with all the other elements we observe today.