Nucleosynthesis in the Cd-In-Sn Region
Abstract
The abundance contributions from the possible nucleosynthesis mechanisms to the rare isotopes In-113, Sn-114, and Sn-115 are investigated. The level scheme of Cd-113 was studied via the (n, n-prime gamma) reaction up to 2.5 MeV excitation energy, searching for gateway levels that can provide for thermal equilibration of ground state and isomer under stellar conditions. The experiment confirmed the lowest gateway level at 522 keV, which provides for thermal equilibrium at temperatures above 108 K, resulting in the destruction of the isomer in all plausible s-process scenarios. Accordingly, the importance of the branching at Cd-113 is strongly reduced, allowing only for small s-process yields of In-113, Sn-114, and Sn-115 of less than 0.3%, less than 0.5%, and less than 8%, regardless of the model used. The r-contributions to these isotopes were found to range between 0% and 40%, depending on the post-r-process conditions, and are also not sufficient to account for the observed abundances. For Sn-114 the remaining abundance contribution can be accounted for by recent p-process calculations, but a different production mechanism seems to be required for In-113 and Sn-115.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1994
- DOI:
- Bibcode:
- 1994ApJ...426..357N
- Keywords:
-
- Abundance;
- Atomic Energy Levels;
- Cadmium Isotopes;
- Indium Isotopes;
- Isomers;
- Nuclear Fusion;
- Tin Isotopes;
- Branching (Physics);
- Ionization;
- Ratios;
- Thermalization (Energy Absorption);
- Astrophysics;
- NUCLEAR REACTIONS;
- NUCLEOSYNTHESIS;
- ABUNDANCES