منابع مشابه
Abundances of light elements.
Recent developments in the study of abundances of light elements and their relevance to cosmological nucleosynthesis are briefly reviewed. The simplest model, based on standard cosmology and particle physics and assuming homogeneous baryon density at the relevant times, continues to stand up well.
متن کاملBig Bang Nucleosynthesis and the observed abundances of light elements
The standard model of the early universe is extraordinarily simple: it just assumes a globally isotropic and uniform universe. In the simplest version there is no structure of any kind on scales larger than individual elementary particles; indeed the contents are determined by “just physics”— global expansion governed by relativity, particle interactions governed by the Standard Model, and dist...
متن کاملBig Bang Nucleosynthesis and Abundances of Light Elements
Big Bang nucleosynthesis (BBNS) theory is sketched, indicating the dependence of primordial abundances of D, 3He, 4He and 7Li on the mean baryonic density of the universe and the dependence of 4He on the number of neutrino families and the neutron half-life. Observational data and inferred primordial abundances of these elements are reviewed and shown to be consistent (within errors) either wit...
متن کاملThe Abundances of Light Neutron-Capture Elements in Planetary Nebulae
We present preliminary results from a large-scale survey of the neutron(n)-capture elements Se and Kr in Galactic planetary nebulae (PNe). These elements may be produced in PN progenitors by s-process nucleosynthesis, and brought to the stellar envelope by third dredge-up (TDU). We have searched for [Kr III] 2.199 and [Se IV] 2.287 μm in 120 PNe, and detected one or both lines in 79 objects, fo...
متن کاملSolar Abundances of the Elements
The isotopic compositions of noble gases in the solar wind show high enrichments of light isotopes. When corrected for mass fractionation all five noble gases there can be resolved in terms of the two primitive noble gas components that have been identified in planetary solids. Reasons are presented for assigning the fractionation to a solar process that selectively enriches lighter nuclei at t...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 1993
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.90.11.4789