Supernova nucleosynthesis
Supernova nucleosynthesis refers to the nuclear fusion, or nuclear fission, of matter inside supernovas. Other types of nucleosynthesis include Big Bang nucleosynthesis, Stellar nucleosynthesis, and Cosmic ray spallation.
Supernovae
A supernova is a massive explosion of a star that occurs under two possible scenarios.The first is that a white dwarf star undergoes a nuclear based explosion after it reaches critical mass from absorbing mass from a neighboring star. The second, and more common cause is when a massive star, usually a red giant, loses fuel for the fusion that powers it, it collapses, and combusts from the energy created from the collapse. At
Elements fused
Due to the large amounts of energy released in a supernova explosion much higher temperatures are reached. Higher temperatures allow for an environment where elements up to the atomic mass of 251 are formed, californium being the heaviest known of, though it is only seen as a synthetic element on Earth. In stellar nucleosynthesis, nuclear fusion that powers stars, the maximum weight for an element fused is that of iron, with an atomic mass of 55.845. Fusion of elements as heavy as iron are quite rare and only occur in the largest of stars, leading scientists to believe that most of the elements heavier than oxygen that make life possible were createed in supernovas.
The R-Process
During supernova nucleosynthesis, the R-process (R for rapid) is the reason for supernova's fusion ability. The process is a neutron capture process for radioactive elements which occurs in high neutron density with high temperature conditions. In the r-process nuclei are bombarded with a large neutron flux to form highly unstable neutron rich nuclei which very rapidly decay to form stable neutron rich nuclei. The neutron flux is abnormaly high at about 10²² neutrons per square centimeter per second. Other nucleosynthesis processes are the P-process, and the S-process, the S-process being the one used in stellar nucleosynthesis.