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Gamma-Ray Emission And Nucleosynthesis Of Lithium By Young Pulsars, Donald D. Clayton, Eliahu Dwek
Gamma-Ray Emission And Nucleosynthesis Of Lithium By Young Pulsars, Donald D. Clayton, Eliahu Dwek
Publications
We propose that 7Li is produced in the Galaxy primarily by α-α collisions surrounding newly born pulsars. About 10 percent of the pulsar energy losses are converted to medium-energy α-particles which collide in a dominantly He nebula. The problem of the origin of lithium would be solved by the scenario, and clear-cut tests by nuclear γ-ray astronomy are described.
S-Process Studies: Branching And The Time Scale, Richard A. Ward, Michael J. Newman, Donald D. Clayton
S-Process Studies: Branching And The Time Scale, Richard A. Ward, Michael J. Newman, Donald D. Clayton
Publications
The theory of S-process heavy-element formation is reformulated to allow for competition between beta decay and neutron capture at various nuclei along the path. Solutions to the resulting branching network equations are presented (under the assumption of constant temperature and neutron flux) that do not require steady flow for the neutron current. Using the exponential exposure distribution rho (tau) =G exp(-tau/tau0) and recently calculated temperature-dependent beta-decay rates, comparison of several key branches yields the following average conditions for the solar-system S-process environment: Tapprox. =3.1 x 108 K, n/subn/approx. =1.6 x 107 neutrons cm-3. For tau0=0.25 n mb-1 we find that …