Lead, platinum, and other heavy elements in the primary cosmic radiation - HEAO 3 results
Abstract
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.
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.Attached Files
Published - 1985ApJ___297__111B.pdf
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Additional details
- Eprint ID
- 44776
- Resolver ID
- CaltechAUTHORS:20140408-134101988
- NASA
- NAS 8-27976
- NASA
- NAS 8-27977
- NASA
- NAS 8-27978
- NASA
- NGR 05-002-160
- NASA
- NGR 24-005-050
- NASA
- NGR 26-008-001
- Created
-
2014-04-08Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Space Radiation Laboratory