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Boron cosmochemistry. Part II: Boron nucleosynthesis and condensation temperature
Author(s) -
Zhai Mingzhe
Publication year - 1995
Publication title -
meteoritics
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0026-1114
DOI - 10.1111/j.1945-5100.1995.tb01171.x
Subject(s) - meteorite , cosmic ray , cosmochemistry , physics , chondrite , nucleosynthesis , interstellar medium , boron , astrophysics , solar system , supernova , astrochemistry , abundance of the chemical elements , abundance (ecology) , isotopes of boron , formation and evolution of the solar system , cosmic ray spallation , astrobiology , ultra high energy cosmic ray , galaxy , nuclear physics , fishery , biology
— The new B solar‐system abundance calculated by Zhai and Shaw (1994), 16.9 atoms/10 6 Si (or 606 atoms/10 12 H) is used to reevaluate the different possibilities of LiBeB (except 7 Li) nucleosynthesis. The revised abundances support two models: (1) Light elements were formed by continual bombardment of interstellar medium (ISM) by galactic cosmic rays (GCRs), but these galactic cosmic rays should contain a very intense low‐energy component, in the form of E −5 which cannot be observed near the Earth due to solar modulation effects; (2) Light elements are a mixture of two sources. In the first source, light elements were synthesized by continual bombardment of interstellar medium by galactic cosmic rays. In the second source, they were made by the interactions of C and O nuclei ejected from supernovae with the H and He in the surrounding gas. The first source constitutes ∼46% of total B. The Si‐normalized and CI‐meteorite‐normalized abundances of common and volatile elements in carbonaceous chondrites show a linear correlation with their condensation temperatures. Using this relationship and the normalized B abundances in CM, CO, and CV meteorites, we can estimate the B condensation temperature to be ∼910 K, which is similar to Ga.