Constraints on the Time Delay between Nucleosynthesis and Cosmic-Ray Acceleration from Observations of ^(59)Ni and ^(59)Co
Creators
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1.
Jet Propulsion Lab
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2.
Washington University in St. Louis
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3.
Goddard Space Flight Center
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4.
California Institute of Technology
Abstract
Measurements of the abundances of cosmic-ray ^(59)Ni and ^(59)Co are reported from the Cosmic-Ray Isotope Spectrometer (CRIS) on the Advanced Composition Explorer. These nuclides form a parent-daughter pair in a radioactive decay which can occur only by electron capture. This decay cannot occur once the nuclei are accelerated to high energies and stripped of their electrons. The CRIS data indicate that the decay of ^(59)Ni to ^(59)Co has occurred, leading to the conclusion that a time longer than the 7.6 × 10^4 yr half-life of ^(59)Ni elapsed before the particles were accelerated. Such long delays indicate the acceleration of old, stellar or interstellar material rather than fresh supernova ejecta. For cosmic-ray source material to have the composition of supernova ejecta would require that these ejecta not undergo significant mixing with normal interstellar gas before ~10^5 yr has elapsed.
Additional Information
© 1999 American Astronomical Society. Received 1999 February 26; accepted 1999 July 15; published 1999 August 18. We are grateful to the large group of dedicated individuals that contributed to the development of the CRIS instrument (listed in Stone et al. 1998). We thank W. R. Webber for providing new cross section estimates prior to publication. This research was supported by the National Aeronautics and Space Administration at the California Institute of Technology (under grant NAG5-6912), the Jet Propulsion Laboratory, the Goddard Space Flight Center, and Washington University and by the McDonnell Center for the Space Sciences at Washington University.Attached Files
Published - 1538-4357_523_1_L61.pdf
Files
1538-4357_523_1_L61.pdf
Additional details
Additional titles
- Alternative title
- Constraints on the Time Delay between Nucleosynthesis and Cosmic-Ray Acceleration from Observations of 59Ni and 59Co
Identifiers
- Eprint ID
- 49121
- Resolver ID
- CaltechAUTHORS:20140902-132158815
Funding
- NASA
- NAG5-6912
- JPL
- Goddard Space Flight Center
- Washington University McDonnell Center for the Space Sciences
Dates
- Created
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2014-09-04Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
Caltech Custom Metadata
- Caltech groups
- Space Radiation Laboratory , Physics Department
- Other Numbering System Name
- Space Radiation Laboratory
- Other Numbering System Identifier
- 1999-52