r-process


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r-process

A rapid process of nucleosynthesis that is thought to occur when there is a very high flux of neutrons, as in certain supernova explosions. All nuclei with a mass number greater than bismuth–209 (see s-process) and all neutron-rich isotopes heavier than iron have been produced by the r-process. The process involves the capture by a nucleus of two or more neutrons in quick succession. The nucleus will then undergo chains of beta decay, this beta-particle (electron) emission having been suppressed during the rapid capture process. The decay product will be a stable neutron-rich nucleus. Many heavy nuclei can be produced both by the r- and the s-process.

r-process

[′är ‚prä·səs]
(nuclear physics)
The synthesis of elements and nuclides in supernovas through rapid captures of neutrons in a matter of seconds, followed by beta decay.
References in periodicals archive ?
The new data will be compared with theoretical mass models and included in r-process calculations performed for various astrophysical sites.
The researchers hope that they might be able to detect the imploding neutron stars as kilonovae, or explosions much dimmer than supernovae that could hint to this so-called r-process formation.
Many of the universe's heaviest elements form primarily through the r-process, a chain of reactions through which atomic nuclei climb the periodic table, swallowing up neutrons and decaying radioactively.
For 50 years, astronomers and nuclear physicists have modeled this rapid process, named the r-process, in order to unravel the cosmic history of the elements.
Poster topics include the magnesium abundance in 52 B stars, an infrared survey of neutron capture elements in planetary nebulae, new r-process enhanced stars found in the HK-II survey, and the origin of sulfur.
The r-process forges the heaviest elements such as gold and uranium, But its astrophysical production site still has to be clarified.
Both elements arise in the r-process, which occurs in supernovae and neutron-star mergers when neutrons bombard nuclei rapidly to create small quantities of heavy elements.
R-process elements are those heavy elements that are formed by "rapid" processes, most likely at the heart of a collapsing star or in the collision of two neutron stars.
The decompression of neutron-rich matter provides excellent conditions for producing r-process elements, heavy neutron-rich elements whose astrophysical production site has not yet been identified.
The r-process is less well understood, but its primary realm of activity is probably the reactions that occur during a supernova explosion, one where a massive star's core collapses at the end of its life.
The outcome is of extreme importance in understanding the nucleosynthesis impact of the first stars, the chemical evolution of galaxies and the origin of all elements, including those processes with still highly uncertain origins/sites like the r-process, the nu/p-process or the p-process.