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Title: Galactic chemical evolution and solar s-process abundances: Dependence on the {sup 13}C-pocket structure

We study the s-process abundances (A ≳ 90) at the epoch of the solar system formation. Asymptotic giant branch yields are computed with an updated neutron capture network and updated initial solar abundances. We confirm our previous results obtained with a Galactic chemical evolution (GCE) model: (1) as suggested by the s-process spread observed in disk stars and in presolar meteoritic SiC grains, a weighted average of s-process strengths is needed to reproduce the solar s distribution of isotopes with A > 130; and (2) an additional contribution (of about 25%) is required in order to represent the solar s-process abundances of isotopes from A = 90 to 130. Furthermore, we investigate the effect of different internal structures of the {sup 13}C pocket, which may affect the efficiency of the {sup 13}C(α, n){sup 16}O reaction, the major neutron source of the s process. First, keeping the same {sup 13}C profile adopted so far, we modify by a factor of two the mass involved in the pocket; second, we assume a flat {sup 13}C profile in the pocket, and we test again the effects of the variation of the mass of the pocket. We find that GCE s predictions at themore » epoch of the solar system formation marginally depend on the size and shape of the {sup 13}C pocket once a different weighted range of {sup 13}C-pocket strengths is assumed. We obtain that, independently of the internal structure of the {sup 13}C pocket, the missing solar system s-process contribution in the range from A = 90 to 130 remains essentially the same.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4]
  1. INAF-Astrophysical Observatory Turin, Turin (Italy)
  2. Department of Physics, University of Turin, Turin (Italy)
  3. Joint Institute for Nuclear Astrophysics (JINA), Department of Physics, University of Notre Dame, Notre Dame IN (United States)
  4. Karlsruhe Institute of Technology, Campus Nord, Institut für Kernphysik, Karlsruhe (Germany)
Publication Date:
OSTI Identifier:
22356879
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; ASYMPTOTIC SOLUTIONS; CARBON 13; EFFICIENCY; GALAXIES; MASS; NEUTRON REACTIONS; NEUTRON SOURCES; OXYGEN 16; S PROCESS; SILICON CARBIDES; SOLAR SYSTEM; SUN