核物理学者、太陽系における放射性ベリリウムの起源に疑問(Nuclear physicists question origin of radioactive beryllium in the solar system)

2024-07-31 オークリッジ国立研究所(ORNL)

＜関連情報＞

• https://www.ornl.gov/news/nuclear-physicists-question-origin-radioactive-beryllium-solar-system
• https://journals.aps.org/prc/abstract/10.1103/PhysRevC.106.015803

10Be(p,α)7Li反応率における低空共鳴の役割と太陽系形成への影響 Role of low-lying resonances for the 10Be⁢(p,α)⁢7Li reaction rate and implications for the formation of the Solar System

A. Sieverding, J. S. Randhawa, D. Zetterberg, R. J. deBoer, T. Ahn, R. Mancino, G. Martínez-Pinedo, and W. R. Hix
Physical Review C  Published 12 July 2022
DOI:https://doi.org/10.1103/PhysRevC.106.015803

Abstract

Evidence for the presence of short-lived radioactive isotopes when the Solar System formed is preserved in meteorites, providing insights into the conditions at the birth of our Sun. A low-mass core-collapse supernova had been postulated as a candidate for the origin of ¹⁰Be, reinforcing the idea that a supernova triggered the formation of the Solar System. We present a detailed study of the production of ¹⁰Be by the process in supernovae, which is very sensitive to the reaction rate of the major destruction channel, 10Be⁢(ｐ,α)^7⁢Li. With data from recent nuclear experiments that show the presence of a resonant state in ¹¹B at ≈193 keV, we derive new values for the ¹⁰Be⁢(ｐ,α)⁷⁢Li reaction rate, which are significantly higher than previous estimates. We show that, with the new ¹⁰Be⁢(ｐ,α)⁷⁢Li reaction rate, a low-mass CCSN is unlikely to produce enough ¹⁰Be to explain the observed 10Be/9Be ratio in meteorites, even for a wide range of neutrino spectra considered in our models.