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Supernova nucleosynthesis is the nucleosynthesis of chemical elements in supernova explosions.. In sufficiently massive stars, the nucleosynthesis by fusion of lighter elements into heavier ones occurs during sequential hydrostatic burning processes called helium burning, carbon burning, oxygen burning, and silicon burning, in which the byproducts of one nuclear fuel become, after ...
The most convincing proof of explosive nucleosynthesis in supernovae occurred in 1987 when those gamma-ray lines were detected emerging from supernova 1987A. Gamma-ray lines identifying 56 Co and 57 Co nuclei, whose half-lives limit their age to about a year, proved that their radioactive cobalt parents created them.
There are three natural candidate sites for r-process nucleosynthesis where the required conditions are thought to exist: low-mass supernovae, Type II supernovae, and neutron star mergers. [15] Immediately after the severe compression of electrons in a Type II supernova, beta-minus decay is blocked.
This final burning in massive stars, called explosive nucleosynthesis or supernova nucleosynthesis, is the final epoch of stellar nucleosynthesis. A stimulus to the development of the theory of nucleosynthesis was the discovery of variations in the abundances of elements found in the universe. The need for a physical description was already ...
The s-process is believed to occur mostly in asymptotic giant branch stars, seeded by iron nuclei left by a supernova during a previous generation of stars. In contrast to the r-process which is believed to occur over time scales of seconds in explosive environments, the s-process is believed to occur over time scales of thousands of years, passing decades between neutron captures.
The intensely radioactive nature of the ejecta gases was first calculated on sound nucleosynthesis grounds in the late 1960s, and this has since been demonstrated as correct for most supernovae. [147] It was not until SN 1987A that direct observation of gamma-ray lines unambiguously identified the major radioactive nuclei. [148]
The term p-process (p for proton) is used in two ways in the scientific literature concerning the astrophysical origin of the elements (nucleosynthesis).Originally it referred to a proton capture process which was proposed to be the source of certain, naturally occurring, neutron-deficient isotopes of the elements from selenium to mercury.
The position and timing mean that it may have been an observation of the Cassiopeia A progenitor supernova. [9] Another suggestion from recent cross-disciplinary research is that the supernova was the "noon day star", observed in 1630, that was thought to have heralded the birth of Charles II, the future monarch of Great Britain. [10]