skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Isotopic anomalies from neutron reactions during explosive carbon burning

Abstract

We examine the possibility that the newly discovered correlated isotopic anomalies for heavy elements in the Allende meteorite were synthesized in the secondary neutron-capture episode during the explosive carbon burning (ECB) : the possible source of the /sup 16/O and /sup 26/Al anomalies. ECB calculations under typical conditions were first performed to generate time profiles of temperature, density, and free-particle concentrations. These quantities were inputted into a general neutron-capture code which caLculates the isotopic pattern resulting from exposing the preexisting heavy ''seed'' nuclei to these free particles during the ECB conditions. Comparison with published data shows that under certain conditions anomalies can be explained qualitatively by such a process. Furthermore, within an uncertainty of a factor of 5, which is typical of nucleosynthetic calculations in this region, the observations can be fitted quantitatively by this process. This process may provide a viable alternative to the classical r-process and the r-process in the explosive helium-burning zone which have also been proposed to expalin the anomalies. Unlike the r-process, the present interpretation avoids the problem of the Sr isotopic data. It may also resolve the conflict between the time scales inferred from /sup 129/I, /sup 224/Pu, /sup 26/Al, but recent /sup 107/Pdmore » results indicate otherwise. Experimental studies of Zr and Ce isotopic composition are proposed to test this model.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Enrico Fermi Institute, University of Chicago
OSTI Identifier:
5731307
Resource Type:
Journal Article
Journal Name:
Astrophys. J.; (United States)
Additional Journal Information:
Journal Volume: 232:3
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARBON BURNING; ISOTOPES; NEUTRON REACTIONS; CAPTURE; NUCLEOSYNTHESIS; R PROCESS; STAR EVOLUTION; ABUNDANCE; CHEMICAL COMPOSITION; HELIUM BURNING; SOLAR SYSTEM; STAR BURNING; BARYON REACTIONS; HADRON REACTIONS; NUCLEAR REACTIONS; NUCLEON REACTIONS; 640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar, Radio & X-Ray Sources

Citation Formats

Lee, T., Schramm, D.N., Wefel, J.P., and Blake, J.B. Isotopic anomalies from neutron reactions during explosive carbon burning. United States: N. p., 1979. Web. doi:10.1086/157346.
Lee, T., Schramm, D.N., Wefel, J.P., & Blake, J.B. Isotopic anomalies from neutron reactions during explosive carbon burning. United States. doi:10.1086/157346.
Lee, T., Schramm, D.N., Wefel, J.P., and Blake, J.B. Sat . "Isotopic anomalies from neutron reactions during explosive carbon burning". United States. doi:10.1086/157346.
@article{osti_5731307,
title = {Isotopic anomalies from neutron reactions during explosive carbon burning},
author = {Lee, T. and Schramm, D.N. and Wefel, J.P. and Blake, J.B.},
abstractNote = {We examine the possibility that the newly discovered correlated isotopic anomalies for heavy elements in the Allende meteorite were synthesized in the secondary neutron-capture episode during the explosive carbon burning (ECB) : the possible source of the /sup 16/O and /sup 26/Al anomalies. ECB calculations under typical conditions were first performed to generate time profiles of temperature, density, and free-particle concentrations. These quantities were inputted into a general neutron-capture code which caLculates the isotopic pattern resulting from exposing the preexisting heavy ''seed'' nuclei to these free particles during the ECB conditions. Comparison with published data shows that under certain conditions anomalies can be explained qualitatively by such a process. Furthermore, within an uncertainty of a factor of 5, which is typical of nucleosynthetic calculations in this region, the observations can be fitted quantitatively by this process. This process may provide a viable alternative to the classical r-process and the r-process in the explosive helium-burning zone which have also been proposed to expalin the anomalies. Unlike the r-process, the present interpretation avoids the problem of the Sr isotopic data. It may also resolve the conflict between the time scales inferred from /sup 129/I, /sup 224/Pu, /sup 26/Al, but recent /sup 107/Pd results indicate otherwise. Experimental studies of Zr and Ce isotopic composition are proposed to test this model.},
doi = {10.1086/157346},
journal = {Astrophys. J.; (United States)},
number = ,
volume = 232:3,
place = {United States},
year = {1979},
month = {9}
}