Cosmic-Ray Record in Solar System Matter

Abstract We report xenon isotopic abundances observed in the stepwise release of noble gases in a highpurity metal separate of the Forest Vale (H4) chondrite. We identify a 244Pu-derived fission component, due to recoils into the metal, a cosmic-ray-produced spallation component and a new trapped component (FVM; 132Xe: 134Xe: 136Xe = 3.16:1.235:1.000) which is isotopically distinct from known solar system reservoirs. We discuss several processes which might account for observed isotopic shifts and conclude that the signature of FVM xenon may provide clues regarding the origin of chondritic metal.

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A New Determination of Muon Directional Coupling Coefficients

Publications of the Astronomical Society of Australia ◽

10.1017/s132335800001119x ◽

1968 ◽

Vol 1 (4) ◽

pp. 154-157

Author(s):

D. J. Cooke ◽

A. G. Fenton

Keyword(s):

Cosmic Rays ◽

Solar System ◽

Cosmic Ray ◽

Accurate Information ◽

Coupling Coefficients ◽

The Earth ◽

Directional Coupling ◽

Cosmic Ray Flux ◽

Primary Cosmic Rays

Primary cosmic rays passing through the solar system carry with them valuable information about solar and astrophysical phenomena in the form of intensity and spectral variations. In order that this information be efficiently extracted from observations of the directional cosmic-ray flux at the surface of the Earth, it is essential to have accurate information available to enable the relating of the observed secondary cosmic-ray directions of motion and intensity to those outside the range of the disturbing terrestrial influences.

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Carbonaceous chondrite meteorites experienced fluid flow within the past million years

Science ◽

10.1126/science.abc8116 ◽

2021 ◽

Vol 371 (6525) ◽

pp. 164-167

Author(s):

Simon Turner ◽

Lucy McGee ◽

Munir Humayun ◽

John Creech ◽

Brigitte Zanda

Keyword(s):

Fluid Flow ◽

Solar System ◽

Cosmic Ray ◽

Parent Body ◽

Uranium Isotopes ◽

The Past ◽

Uranium Ion ◽

Impact Heating ◽

The Impact ◽

Cosmic Ray Exposure Age

Carbonaceous chondritic meteorites are primordial Solar System materials and a source of water delivery to Earth. Fluid flow on the parent bodies of these meteorites is known to have occurred very early in Solar System history (first <4 million years). We analyze short-lived uranium isotopes in carbonaceous chondrites, finding excesses of 234-uranium over 238-uranium and 238-uranium over 230-thorium. These indicate that the fluid-mobile uranium ion U6+ moved within the past few 100,000 years. In some meteorites, this time scale is less than the cosmic-ray exposure age, which measures when they were ejected from their parent body into space. Fluid flow occurred after melting of ice, potentially by impact heating, solar heating, or atmospheric ablation. We favor the impact heating hypothesis, which implies that the parent bodies still contain ice.

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Molecules in Comets: A Tool to Estimate the Low Energy Cosmic Ray Flux Outside the Solar System?

Symposium - International Astronomical Union ◽

10.1017/s0074180900154452 ◽

1987 ◽

Vol 120 ◽

pp. 443-445

Author(s):

Valerio Pirronello

Keyword(s):

Solar System ◽

Chemical Species ◽

Cosmic Ray ◽

Low Energy ◽

Chemical Modifications ◽

Cometary Nuclei ◽

First Time ◽

Cosmic Ray Flux

It is described a method for evaluating the low energy cosmic ray flux outside the heliosphere. It is based on the chemical modifications induced in cometary nuclei by impinging ions and on the release of synthesized chemical species by comets entering for the first time into the inner solar system.

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Cosmic ray hazards in the solar system

AIAA Journal ◽

10.2514/3.2830 ◽

1965 ◽

Vol 3 (2) ◽

pp. 193-201

Author(s):

S. N. MlLFORD

Keyword(s):

Solar System ◽

Cosmic Ray

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The Accuracy of Radiocarbon Dates

Antiquity ◽

10.1017/s0003598x00029987 ◽

1963 ◽

Vol 37 (147) ◽

pp. 213-219 ◽

Cited By ~ 7

Author(s):

W. F. Libby

Keyword(s):

Magnetic Field ◽

Solar System ◽

Cosmic Ray ◽

Average Life ◽

Radiocarbon Dates ◽

Cosmic Ray Intensity ◽

Rapid Mixing ◽

The Past ◽

The Earth ◽

The Magnetic Field

The first test of the accuracy of dates obtained by the radiocarbon technique was made by determining whether dates so obtained agreed with the historical dates for materials of known age (n. 1). The validity of the radiocarbon method continues to be an important question, especially in the light of the numerous results that have been accumulated and the greater precision of the technique during the past few years (n. 2).The radiocarbon content of the biosphere depends on three supposedly independent geophysical quantities: (i) the average cosmic ray intensity over a period of 8000 years (the average life of radiocarbon) as measured in our solar system but outside the earth's magnetic field (n. 1); (ii) the magnitude (but not the orientation, because of the relatively rapid mixing over the earth's surface) of the magnetic field in the vicinity of the earth, averaged over the same period (n. 1,3); and (iii) the degree of mixing of the oceans during the same period (n. 1). The question of the accuracy of radiocarbon dates therefore is of interest to geophysicists in general as well as to the archaeologists, geologists and historians who use the dates.Previous workers in this area (n. 1, 2) have reported some discrepancies, and it is the purpose here to consider the matter further.

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Cosmic-ray nuclei up to 10 10 eV/u in the galaxy

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1975.0002 ◽

1975 ◽

Vol 277 (1270) ◽

pp. 319-348 ◽

Cited By ~ 11

Keyword(s):

Cosmic Rays ◽

Solar System ◽

Cross Sections ◽

Cosmic Ray ◽

Interstellar Space ◽

Heavy Nuclei ◽

Hydrogen Atoms ◽

Interstellar Gas ◽

The Galaxy ◽

Ionization Cross Sections

O f the nuclear cosmic rays arriving in the vicinity of Earth from interstellar space, more than 90% have energies less than 1010 eV /u.f Some effects of their modulation (including deceleration) in the Solar System are briefly discussed. The origin of particles at energies < 107 eV/u is still obscure. They could be due to stellar explosions or to solar emissions, or perhaps to interaction of interstellar gas with the solar wind. Between 108 and 1010 eV/u, the composition appears constant to ca. 30% within the statistics of available data. Cosmic rays traverse a mean path length of 6 g/cm 2 in a medium assumed to contain nine hydrogen atoms for each helium atom. Spallation reactions occurring in this medium result in enhancement of many cosmic-ray elements that are more scarce in the general abundances by several orders of magnitude. Cosmic-ray dwell time in the Galaxy seems to be < 107 years. The source composition of cosmic rays has been derived for elements with atomic numbers 1 ≤ Z ≤ 26. A comparison with abundances in the Solar System implies that the latter is richer in hydrogen and helium by a factor of ca. 20, in N and O by ca. 5, and in C by a factor of ca.2. Possible interpretations invoke (a) nucleosynthesis of cosmic rays in certain sources, e.g. supernovae, or (b) models of selective injection that depend, e.g. on ionization potentials or ionization cross sections. Calculated isotopic abundances of arriving cosmic rays are compared with the observed values now becoming available, and found to be in general agreement. Recent progress in probing the composition and spectrum of ultra-heavy nuclei is outlined.

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