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Lead, platinum, and other heavy elements in the primary cosmic radiation - HEAO 3 results

Binns, W. R. and Brewster, N. R. and Fixsen, D. J. and Garrard, T. L. and Israel, M. H. and Klarmann, J. and Newport, B. J. and Stone, E. C. and Waddington, C. J. (1985) Lead, platinum, and other heavy elements in the primary cosmic radiation - HEAO 3 results. Astrophysical Journal, 297 (1). pp. 111-118. ISSN 0004-637X.

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From an analysis of 580 days of exposure of the Heavy Nuclei Experiment on the HEAO 3 spacecraft, we have selected 322 nuclei with reasonable charge resolution, E ≥ 1.3 GeV n^(-1) and Z ≥ 50. These data show a defined abundance peak in the "platinum" (74 ≤ Z ≤ 80) region, a small abundance of "lead" (81 ≤ Z ≤ 83), and a significant number of "secondary" nuclei in the 62 ≤ Z ≤ 73 range. The deduced ratio in space of 0.25 ± 0.09 for "Pb/Pt" is distinctly lower than that predicted by any of the standard models for cosmic-ray sources and propagation effects. Although this low ratio suggests an enrichment in the cosmic-ray source of products of r-process nucleosynthesis, it may rather be an indication that the Pb abundance is suppressed by a source fractionation effect, or that there is less Pb in the solar system than is assumed in the standard compilations.

Item Type:Article
Related URLs:
URLURL TypeDescription
Binns, W. R.0000-0001-6110-3407
Israel, M. H.0000-0002-8104-208X
Stone, E. C.0000-0002-2010-5462
Additional Information:© 1985 American Astronomical Society. Received 1985 February 1; accepted 1985 April 9. We thank L. Atchison for assistance in programming for data analysis. The research was supported in part by NASA under contracts NAS 8-27976, 77, 78, and grants NGR 05-002-160, 24-005-050, and 26-008-001.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
NASANAS 8-27976
NASANAS 8-27977
NASANAS 8-27978
NASANGR 05-002-160
NASANGR 24-005-050
NASANGR 26-008-001
Subject Keywords:cosmic rays: abundances
Issue or Number:1
Record Number:CaltechAUTHORS:20140408-134101988
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Official Citation:Lead, platinum, and other heavy elements in the primary cosmic radiation - HEAO 3 results Binns, W. R.; Israel, M. H.; Brewster, N. R.; Fixsen, D. J.; Garrard, T. L. Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 297, Oct. 1, 1985, p. 111-118. (ApJ Homepage) Publication Date: 10/1985
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:44776
Deposited By: Ruth Sustaita
Deposited On:08 Apr 2014 22:50
Last Modified:09 Mar 2020 13:18

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