Production of Light Elements in the Solar System

概要

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In order to make clear the early history of the solar system, the production of light elements Li, Be and B by solar cosmic rays are studied. The isotopic ratios of Li and B can be explained by assuming the dominance of the alpha-alpha reactions and the spallation by protons, respectively, induced by high rigidity solar cosmic rays, the characteristic rigidity R_0 being 450-700MV and the alpha-proton ratio j_α/j_p being 1~1/6. As there is no experimental data of α-α reactions at this high energy region, we estimate their cross sections from those of inverse reactions such as (p,α), (d,α) and (np,α) for intermediate weight nuclei. The absence of the spallation by alpha particles is explained by assuming an inhomogeneous model that the target material rich in H and He gases encloses the target material rich in CNONe, and heavier nuclei, and the proton flux can reach the inner region but the alpha flux stops in the outer layer before it interacts with heavier elements. The planets might pass such an inhomogeneous model in their formation stage.
理論物理学刊行会の論文
1972-07-25