TY - JOUR
T1 - Reexamining the temperature and neutron density conditions for r-process nucleosynthesis with augmented nuclear mass models
AU - Xu, X. D.
AU - Sun, B.
AU - Niu, Z. M.
AU - Li, Z.
AU - Qian, Y. Z.
AU - Meng, J.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2013/1/28
Y1 - 2013/1/28
N2 - We explore the effects of nuclear masses on the temperature and neutron density conditions required for r-process nucleosynthesis using four nuclear mass models augmented by the latest atomic mass evaluation. For each model we derive the conditions for producing the observed abundance peaks at mass numbers A∼80, 130, and 195 under the waiting-point approximation and further determine the sets of conditions that can best reproduce the r-process abundance patterns (r-patterns) inferred for the solar system and observed in metal-poor stars of the Milky Way halo. In broad agreement with previous studies, we find that (1) the conditions for producing abundance peaks at A∼80 and 195 tend to be very different, which suggests that, at least for some nuclear mass models, these two peaks are not produced simultaneously; (2) the typical conditions required by the critical waiting-point (CWP) nuclei with the N=126 closed neutron shell overlap significantly with those required by the N=82 CWP nuclei, which enables coproduction of abundance peaks at A∼130 and 195 in accordance with observations of many metal-poor stars; and (3) the typical conditions required by the N=82 CWP nuclei can reproduce the r-pattern observed in the metal-poor star HD 122563, which differs greatly from the solar r-pattern. We also examine how nuclear mass uncertainties affect the conditions required for the r-process and identify some key nuclei including 76Ni to 78Ni, 82Zn, 131Cd, and 132Cd for precise mass measurements at rare-isotope beam facilities.
AB - We explore the effects of nuclear masses on the temperature and neutron density conditions required for r-process nucleosynthesis using four nuclear mass models augmented by the latest atomic mass evaluation. For each model we derive the conditions for producing the observed abundance peaks at mass numbers A∼80, 130, and 195 under the waiting-point approximation and further determine the sets of conditions that can best reproduce the r-process abundance patterns (r-patterns) inferred for the solar system and observed in metal-poor stars of the Milky Way halo. In broad agreement with previous studies, we find that (1) the conditions for producing abundance peaks at A∼80 and 195 tend to be very different, which suggests that, at least for some nuclear mass models, these two peaks are not produced simultaneously; (2) the typical conditions required by the critical waiting-point (CWP) nuclei with the N=126 closed neutron shell overlap significantly with those required by the N=82 CWP nuclei, which enables coproduction of abundance peaks at A∼130 and 195 in accordance with observations of many metal-poor stars; and (3) the typical conditions required by the N=82 CWP nuclei can reproduce the r-pattern observed in the metal-poor star HD 122563, which differs greatly from the solar r-pattern. We also examine how nuclear mass uncertainties affect the conditions required for the r-process and identify some key nuclei including 76Ni to 78Ni, 82Zn, 131Cd, and 132Cd for precise mass measurements at rare-isotope beam facilities.
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U2 - 10.1103/PhysRevC.87.015805
DO - 10.1103/PhysRevC.87.015805
M3 - Article
AN - SCOPUS:84873592641
SN - 0556-2813
VL - 87
JO - Physical Review C - Nuclear Physics
JF - Physical Review C - Nuclear Physics
IS - 1
M1 - 015805
ER -