NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
r-process nucleosynthesis in dynamic helium-burning environmentsThe results of an extended examination of r-process nucleosynthesis in helium-burning enviroments are presented. Using newly calculated nuclear rates, dynamical r-process calculations have been made of thermal runaways in helium cores typical of low-mass stars and in the helium zones of stars undergoing supernova explosions. These calculations show that, for a sufficient flux of neutrons produced by the C-13 neutron source, r-process nuclei in solar proportions can be produced. The conditions required for r-process production are found to be 10 to the 20th-10 to the 21st neutrons per cubic centimeter for times of 0.01-0.1 s and neutron number densities in excess of 10 to the 19th per cubic centimeter for times of about 1 s. The amount of C-13 required is found to be exceedingly high - larger than is found to occur in any current stellar evolutionary model. It is thus unlikely that these helium-burning environments are responsible for producing the bulk of the r-process elements seen in the solar system.
Document ID
19850061603
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Cowan, J. J. (Oklahoma, University Norman, United States)
Cameron, A. G. W. (Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Truran, J. W. (Illinois, University Urbana, United States)
Date Acquired
August 12, 2013
Publication Date
July 15, 1985
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 294
ISSN: 0004-637X
Subject Category
ASTROPHYSICS
Funding Number(s)
CONTRACT_GRANT: NSF AST-81-19545
CONTRACT_GRANT: NGR-22-007-272
CONTRACT_GRANT: NSF AST-82-14964
CONTRACT_GRANT: NSF AST-80-18198
Distribution Limits
Public
Copyright
Other