Hostname: page-component-6766d58669-7cz98 Total loading time: 0 Render date: 2026-05-16T19:23:02.955Z Has data issue: false hasContentIssue false

LiBeB Evolution: Three Models

Published online by Cambridge University Press:  25 May 2016

Reuven Ramaty
Affiliation:
NASA/GSFC, Greenbelt, MD 20771, USA
Richard E. Lingenfelter
Affiliation:
CASS/UCSD, LaJolla, CA 92093, USA
Benzion Kozlovsky
Affiliation:
Tel Aviv University, Israel

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the 'Save PDF' action button.

We consider the three principal LiBeB evolutionary models, CRI in which the cosmic-ray source at all epochs of Galactic evolution is the average ISM, CRI+LECR in which metal enriched low energy cosmic rays (LECRs) are superimposed onto the CRI cosmic rays, and CRS in which the cosmic-ray source, accelerated in superbubbles, is constant, independent of the ISM metallicity. By considering the evolutionary trend of log(Be/H) vs. both [Fe/H] and [O/H], we demonstrate that the CRI model is energetically untenable. We present evolutionary trends for 11B/10B and B/Be which, combined with future precision measurements, could distinguish between the CRS and CRI+LECR models. We show that delayed LiBeB synthesis in the CRS model, due to the transport of the cosmic rays, could explain why log(Be/H) is steeper vs. [O/H] than vs. [Fe/H]. We also show that delayed deposition of Fe into star forming regions, due to its incorporation into high velocity dust, could provide an explanation for the possible rise of [O/Fe] with decreasing [Fe/H]. Observations of refractory and volatile α-elements could test this scenario. There seems to be a need for pregalactic or extragalactic 6Li sources.

Information

Type
2. Production and Destruction of the Elements
Copyright
Copyright © Astronomical Society of the Pacific 2000