Open AccessEvolution of Beryllium and Boron in the Inhomogeneous Early Galaxy
Author(s) -
Takeru K. Suzuki,
Yuzuru Yoshii,
Toshitaka Kajino
Publication year - 1999
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/312233
Subject(s) - supernova , physics , ejecta , astrophysics , nucleosynthesis , cosmic ray , galaxy , stars , beryllium , milky way , interstellar medium , halo , spallation , galactic halo , astronomy , nuclear physics , neutron
A model of supernova-driven chemical evolution of the Galactic halo, recentlyproposed by Tsujimoto, Shigeyama, & Yoshii (1999, ApJL, 519, 64), is extendedin order to investigate the evolution of light elements such as Be and B (BeB),which are produced mainly through spallative reactions with Galactic cosmicrays. In this model each supernova sweeps up the surrounding interstellar gasinto a dense shell and directly enriches it with ejecta which consist of heavyelements produced in each Type II supernova with different progenitor masses.We propose a two-component source for GCRs such that both interstellar gas andfresh SN ejecta engulfed in the shell are accelerated by the shock wave. Ourmodel results include: (1) a prediction of the intrinsic scatter in BeB and[Fe/H] abundances within the model, (2) a successful prediction of the observedlinear trend between BeB and [Fe/H], (3) a proposal for using BeB as a cosmicclock, as an alternative to [Fe/H], and (4) a method for possibly constrainingthe BBN model from future observations of metal-poor stars.Comment: 3 color figures in 7 pages, accepted by ApJ Letter
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