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Boron in the Extreme Pop II Star HD 140283 and the Production of Light Elements in the Early Galaxy

B. Edvardsson·B. Gustafsson·S. G. Johansson·D. Kiselman·D. L. Lambert·P. E. Nissen·G. Gilmore
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Abstract

Using observations of the 2496.7 A B I line with the HST GHRS at a nominal resolution of 90,000, we have found the abundance of boron of HD 140283 to be log epsilon_B (= 12 + log (N_B/N_H)) = 0.34 \pm 0.20. This result is found when a significant non-LTE effect in the formation of the B I line is taken into account. The resulting N_B/N_Be ratio is about 17 (in the range 9 -- 34), which is in very good agreement with what is expected from spallation by cosmic rays. We conclude that this origin of Be and B in the Early Galaxy is the most probable of recently suggested formation mechanisms. (Submitted to A&A. Postscript figures available via annymous ftp to "chiron.astro.uu.se" in directory pub/Preprints/P87)

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B. Edvardsson, B. Gustafsson, S. G. Johansson, D. Kiselman, D. L. Lambert, P. E. Nissen, G. Gilmore. 1994-03-01. Boron in the Extreme Pop II Star HD 140283 and the Production of Light Elements in the Early Galaxy. https://arxiv.org/abs/astro-ph/9403002

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