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The boron-to-beryllium ratio in halo stars - A signature of cosmic-ray nucleosynthesis in the early GalaxyWe discuss Galactic cosmic-ray (GCR) spallation production of Li, Be, and B in the early Galaxy with particular attention to the uncertainties in the predictions of this model. The observed correlation between the Be abundance and the metallicity in metal-poor Population II stars requires that Be was synthesized in the early Galaxy. We show that the observations and such Population II GCR synthesis of Be are quantitatively consistent with the big bang nucleosynthesis production of Li-7. We find that there is a nearly model independent lower bound to B/Be of about 7 for GCR synthesis. Recent measurements of B/Be about 10 in HD 140283 are in excellent agreement with the predictions of Population II GCR nucleosynthesis. Measurements of the boron abundance in additional metal-poor halo stars is a key diagnostic of the GCR spallation mechanism. We also show that Population II GCR synthesis can produce amounts of Li-6 which may be observed in the hottest halo stars.
Document ID
19930071064
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Walker, T. P.
(NASA Lewis Research Center Cleveland, OH, United States)
Steigman, G.
(Ohio State Univ. Columbus, United States)
Schramm, D. N.
(Chicago Univ.; NASA/Fermilab Astrophysics Center Batavia, IL, United States)
Olive, K. A.
(Minnesota Univ. Minneapolis, United States)
Fields, B.
(Chicago Univ.; NASA/Fermilab Astrophysics Center Batavia, IL, United States)
Date Acquired
August 16, 2013
Publication Date
August 20, 1993
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 413
Issue: 2
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
93A55061
Distribution Limits
Public
Copyright
Other

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