Portal de Periódicos da CAPES

Implications of a high population 2 B/Be ratio

1995; IOP Publishing; Volume: 439; Linguagem: Inglês

10.1086/175224

1538-4357

Brian D. Fields, Keith A. Olive, David N. Schramm,

Astro and Planetary Science

view Abstract Citations (15) References (31) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Implications of a High Population II B/Be Ratio Fields, Brian D. ; Olive, Keith A. ; Schramm, David N. Abstract The observed B/Be ratio in extreme Pop II stars has been interpreted as evidence of Be and B synthesis by early galactic cosmic rays. However, a recent reanalysis of the boron abundance in the Pop II halo star HD140283 suggests that B/H may be larger than previously reported, by as much as a factor of 4. This would yield a B/Be ratio lying in the range $14 \la {\rm B/Be} \la 50$. The possibility of a high Pop II B/Be ratio stresses the importance of the upper limit to the B/Be ratio arising from cosmic ray production. It is found that the limit to cosmic ray-produced B/Be depends upon the assumed cosmic ray spectrum. For any Pop II comic ray spectrum that is a single power law in either total energy per nucleon or in momentum the B/Be ratio is constrained to lie in the range $7.6 \la$ B/Be $\la 14$. Thus, if the new B/Be ratio is correct, it requires either a bimodal cosmic ray flux with a large low energy component, or for another B source, possibly the proposed $\nu$-process in supernovae, either of which may be helpful in explaining the observed \bor11/\bor10 ratio. Finally, it is noted that the boron reanalysis highlights the uncertainty in our knowledge of the B/Be ratio, and the need for additional data on Be and B abundances. Publication: The Astrophysical Journal Pub Date: February 1995 DOI: 10.1086/175224 arXiv: arXiv:astro-ph/9407099 Bibcode: 1995ApJ...439..854F Keywords: Abundance; Beryllium; Boron; Galactic Cosmic Rays; Mass Ratios; Stellar Composition; Data Reduction; Nuclear Fusion; Spectrum Analysis; Astrophysics; ISM: COSMIC RAYS; NUCLEAR REACTIONS; NUCLEOSYNTHESIS; ABUNDANCES; STARS: POPULATION II; Astrophysics E-Print: 11 pages, LaTeX, 2 postscript figures available via anonymous ftp (oddjob.uchicago.edu, pub/hibeb/), FERMILAB-Pub-94/121-A full text sources arXiv | ADS | data products SIMBAD (3)