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The Phosphorus, Sulfur, Argon, and Calcium Isotopic Composition of the Galactic Cosmic Ray Source

Ogliore, R. C. and Stone, E. C. and Leske, R. A. and Mewaldt, R. A. and Wiedenbeck, M. E. and Binns, W. R. and Israel, M. H. and von Rosenvinge, T. T. and de Nolfo, G. A. and Moskalenko, I. V. (2009) The Phosphorus, Sulfur, Argon, and Calcium Isotopic Composition of the Galactic Cosmic Ray Source. Astrophysical Journal, 695 (1). pp. 666-678. ISSN 0004-637X. doi:10.1088/0004-637X/695/1/666.

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Galactic cosmic ray (GCR) measurements of the phosphorus, sulfur, argon, and calcium isotopes made by the Cosmic Ray Isotope Spectrometer aboard the Advanced Composition Explorer are reported over the energy range from ~100 to ~400 MeV nucleon^(–1). The propagation of cosmic rays through the Galaxy and heliosphere is modeled with constraints imposed by measurements. Isotopic source abundance ratios ^(31)P/^(32)S, ^(34)S/^(32)S, ^(38)Ar/^(36)Ar, and ^(44)Ca/^(40)Ca are deduced. The derived ^(31)P/^(32)S ratio is 2.34 ± 0.34 times larger than the solar system value, lending further credence to the suggestion that refractory elements are enriched in the GCRs due to the sputtering of ions off grains in the cores of superbubbles. By determining the GCR source abundances of argon (a noble gas) and calcium (a refractory), it is determined that material in grains is accelerated to GCR energies a factor of 6.4 ± 0.3 more efficiently than gas-phase material in this charge range. With this information, the dust fraction of phosphorus and sulfur in the interstellar material that is mixed with stellar ejecta to form the GCR seed material is found to be consistent with astronomical observations.

Item Type:Article
Related URLs:
URLURL TypeDescription
Ogliore, R. C.0000-0001-8165-6252
Stone, E. C.0000-0002-2010-5462
Leske, R. A.0000-0002-0156-2414
Mewaldt, R. A.0000-0003-2178-9111
Wiedenbeck, M. E.0000-0002-2825-3128
Binns, W. R.0000-0001-6110-3407
Israel, M. H.0000-0002-8104-208X
von Rosenvinge, T. T.0000-0001-7320-4141
de Nolfo, G. A.0000-0002-3677-074X
Moskalenko, I. V.0000-0003-2272-2103
Additional Information:© 2009 The American Astronomical Society. Received 2008 November 18; accepted 2009 January 13; published 2009 April 1. This work was supported by NASA at the California Institute of Technology (under grant NAG5-12929), the Jet Propulsion Laboratory, the Goddard Space Flight Center, and Washington University. I.V.M. acknowledges NASA and APRA grants for partial support.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:cosmic rays; Galaxy: abundances; ISM: abundances; ISM: bubbles; supernovae: general
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Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2009-12
Issue or Number:1
Record Number:CaltechAUTHORS:20090911-084724861
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Official Citation:The Phosphorus, Sulfur, Argon, and Calcium Isotopic Composition of the Galactic Cosmic Ray Source R. C. Ogliore, E. C. Stone, R. A. Leske, R. A. Mewaldt, M. E. Wiedenbeck, W. R. Binns, M. H. Israel, T. T. von Rosenvinge, G. A. de Nolfo, and I. V. Moskalenko 2009 ApJ 695 666-678 doi: 10.1088/0004-637X/695/1/666.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15754
Deposited By: Tony Diaz
Deposited On:11 Sep 2009 22:23
Last Modified:28 Nov 2022 22:01

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