Efficient method for estimation of fission fragment yields of 
r
-process nuclei

We review recent work examining the influence of fission in rapid neutron capture (r-process) nucleosynthesis which can take place in astrophysical environments. We briefly discuss the impact of uncertain fission barriers and fission rates on the population of heavy actinide species. We demonstrate the influence of the fission fragment distributions for neutron-rich nuclei and discuss currently available treatments, including recent macroscopic-microscopic calculations. We conclude by comparing our nucleosynthesis results directly with stellar data for metal-poor stars rich in r-process elements to consider whether fission plays a role in the so-called ‘universality’ of r-process abundances observed from star to star.

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Fission fragment mass distribution for nuclei in the r-process region

10.1063/1.2713548 ◽

2007 ◽

Author(s):

S. Tatsuda ◽

K. Hashizume ◽

T. Wada ◽

M. Ohta ◽

K. Sumiyoshi ◽

...

Keyword(s):

Mass Distribution ◽

Fission Fragment ◽

Fragment Mass ◽

Process Region ◽

R Process

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Distribution of R- and S-Process Elements in the Galactic Halo

Symposium - International Astronomical Union ◽

10.1017/s0074180900035555 ◽

1988 ◽

Vol 132 ◽

pp. 501-506

Author(s):

C. Sneden ◽

C. A. Pilachowski ◽

K. K. Gilroy ◽

J. J. Cowan

Keyword(s):

Heavy Element ◽

Galactic Halo ◽

Low Noise ◽

Heavy Elements ◽

Process Synthesis ◽

Element Abundances ◽

Halo Stars ◽

Abundance Patterns ◽

R Process ◽

Process Elements

Current observational results for the abundances of the very heavy elements (Z>30) in Population II halo stars are reviewed. New high resolution, low noise spectra of many of these extremely metal-poor stars reveal general consistency in their overall abundance patterns. Below Galactic metallicities of [Fe/H] Ã −2, all of the very heavy elements were manufactured almost exclusively in r-process synthesis events. However, there is considerable star-to-star scatter in the overall level of very heavy element abundances, indicating the influence of local supernovas on element production in the very early, unmixed Galactic halo. The s-process appears to contribute substantially to stellar abundances only in stars more metal-rich than [Fe/H] Ã −2.

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Nuclear Processes Related to the Ap Stars and the Heaviest Chemical Elements

International Astronomical Union Colloquium ◽

10.1017/s0252921100080520 ◽

1976 ◽

Vol 32 ◽

pp. 169-182

Author(s):

B. Kuchowicz

Keyword(s):

Nuclear Physics ◽

Nuclear Reactions ◽

Chemical Elements ◽

Fission Products ◽

Abundance Pattern ◽

Isotopic Shifts ◽

Processed Material ◽

R Process ◽

Ap Stars ◽

Nuclear Processes

SummaryIsotopic shifts in the lines of the heavy elements in Ap stars, and the characteristic abundance pattern of these elements point to the fact that we are observing mainly the products of rapid neutron capture. The peculiar A stars may be treated as the show windows for the products of a recent r-process in their neighbourhood. This process can be located either in Supernovae exploding in a binary system in which the present Ap stars were secondaries, or in Supernovae exploding in young clusters. Secondary processes, e.g. spontaneous fission or nuclear reactions with highly abundant fission products, may occur further with the r-processed material in the surface of the Ap stars. The role of these stars to the theory of nucleosynthesis and to nuclear physics is emphasized.

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