R-process



The r-process is a nucleosynthesis process occurring in core-collapse supernovae (see also supernova nucleosynthesis) responsible for the creation of approximately half of the s-process, which is nucleosynthesis by means of slow neutron captures, primarily occurring in AGB stars, and together these two processes account for a majority of galactic chemical evolution of elements heavier than iron.

History

The r-process was seen to be needed from the relative abundances of isotopes of heavy elements and from a newly published table of s-process and r-process was published in a famous review paper in 1957[1], which proposed the theory of stellar nucleosynthesis and set the frame-work for contemporary nuclear astrophysics.

Nuclear physics

Immediately after a core-collapse supernova, there is an extremely high Atomic mass units below the s-process peaks, as the r-process nuclei decay back towards stability on a constant A line in the chart of nuclides.

Astrophysical sites

The site of the r-process is believed to be core-collapse supernovae (spectral Type Ib, Ic and II), which provide the necessary physical conditions for the R-process. However, the abundance of r-process neutron star mergers (a binary star system comprised of two neutron stars that collide) may also play a role in the production of r-process nuclei, but this has yet to be observationally confirmed.

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Nuclear processes
S-process · P-process · Rp-process

References

  1. ^ E. M. Burbidge, G. R. Burbidge, W. A. Fowler, and F. Hoyle. Reviews of Modern Physics, 29 (1957) 547.
 
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