Secular changes in the xenon and krypton abundances in the solar wind recorded in single lunar grains

Wieler, R.; Kehm, K.; Meshik, A. P.; Hohenberg, C. M.

doi:10.1038/384046a0

Cited by 62 publications

(46 citation statements)

References 16 publications

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“…(1997) showed that the 14N/36Ar ratio is not constant but tends to be higher in lunar soil grains with smaller 36Ar concentrations. Since the concentration ratios among heavy rare gases (Ar/Kr/Xe) are constant in the lunar grains (Wieler et al, 1996), a variable Ar loss is not a plausible explanation of the variable 14NP6Ar ratio. Hence, it seems that the variable 14N/36Ar ratio has to be explained as being due to the addition of nonsolar N, and the ALHA77214 type N carrier seems to be a very good candidate of this nonsolar N. Quantitative examination of the N and rare gas abundances shows that the abundances of N and rare gases in Apollo 79035 can be explained fairly well as mixture of a solar wind component and the ALHA77214 type N and rare gases.…”

Section: Comparison With Other Isotopically Anomalous Nitrogenmentioning

confidence: 99%

Nitrogen components in primitive ordinary chondrites

Sugiura

Kiyota

Hashizume

1998

Meteorit & Planetary Scien

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Abstract-Nitrogen and Ar in more than 20 primitive ordinary chondrites were studied by a stepped combustion method. Several N carriers that are characterized by N isotopic composition, N release pattern and trapped Ar release pattern are recognized in the primitive ordinary chondrites. Large fractions of anomalous N and associated Ar are removed by acid treatment in most cases. The N isotopic anomalies cannot be explained by known presolar grains (with a possible exception of graphite), and some of the N isotopic anomalies may be due to unknown presolar grains. There is no specific relationship between the type of N carriers contained in an ordinary chondrite and the chemical type (H, L, or LL) of the chondrite. It is likely that as a result of impacts, the carriers of isotopically anomalous N were mixed in various parent bodies as rock fragments rather than as individual fine particles. The presence of distinctive N isotopic anomalies in primitive meteorites indicates that the primitive solar nebula may have been heterogeneous either spatially or temporally.

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Section: Comparison With Other Isotopically Anomalous Nitrogenmentioning

confidence: 99%

Nitrogen components in primitive ordinary chondrites

Sugiura

Kiyota

Hashizume

1998

Meteorit & Planetary Scien

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“…Moreover, compared to Ar, the lighter noble gases are expected to be more prone to diffusive losses. Indeed, plots of abundance data from Table 2 (see Kehm et al 2002) ilmenite, plagioclase, and pyroxene are observed to retain implanted solar Ar, Kr, and Xe equally well, while exhibiting widely differing retention properties for the light noble gases (Nichols et al 1994;Wieler et al 1996).…”

Section: Solar Exposure Agesmentioning

confidence: 99%

Noble gas space exposure ages of individual interplanetary dust particles

Kehm

Flynn

Hohenberg

2006

Meteoritics &Amp; Planetary Science

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Abstract-The He, Ne, and Ar compositions of 32 individual interplanetary dust particles (IDPs) were measured using low-blank laser probe gas extraction. These measurements reveal definitive evidence of space exposure. The Ne and Ar isotopic compositions in the IDPs are primarily a mixture between solar wind (SW) and an isotopically heavier component dubbed "fractionated solar" (FS), which could be implantation-fractionated solar wind or a distinct component of the solar corpuscular radiation previously identified as solar energetic particles (SEP). Space exposure ages based on the Ar content of individual IDPs are estimated for a subset of the grains that appear to have escaped significant volatile losses during atmosphere entry. Although model-dependent, most of the particles in this subset have ages that are roughly consistent with origin in the asteroid belt. A short (<1000 years) space exposure age is inferred for one particle, which is suggestive of cometary origin. Among the subset of grains that show some evidence for relatively high atmospheric entry heating, two possess elevated 21 Ne/ 22 Ne ratios generated by extended exposure to solar and galactic cosmic rays. The inferred cosmic ray exposure ages of these particles exceeds 10 7 years, which tends to rule out origin in the asteroid belt. A favorable possibility is that these 21 Ne-rich IDPs previously resided on a relatively stable regolith of an Edgeworth-Kuiper belt or Oort cloud body and were introduced into the inner solar system by cometary activity. These results demonstrate the utility of noble gas measurements in constraining models for the origins of interplanetary dust particles.

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“…These may therefore be expected to contain records of the solar wind from billions of years ago, providing a unique test of models of solar evolution. The potential value of this record was stressed in the conclusions of Wieler et al [10]:…”

Section: Identification and Sampling Of Palaeoregolithsmentioning

confidence: 99%

“…One of the many new pieces of information resulting from the Apollo missions was that solar wind, and galactic cosmic ray particles, are efficiently implanted in the lunar regolith [10]. A regolith is formed when a fresh surface is exposed for millions of years to the flux of micrometeorites which constantly impinges on the lunar surface.…”

Section: Identification and Sampling Of Palaeoregolithsmentioning

confidence: 99%

The scientific case for renewed human activities on the Moon

Crawford

2004

Space Policy

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It is over thirty years since the last human being stood on the lunar surface, and I will argue that this long hiatus in human exploration has been to the detriment of lunar and planetary science. The primary scientific importance of the Moon lies in the record it preserves of the early evolution of a terrestrial planet, and of the near-Earth cosmic environment in the first billion years or so of Solar System history. This record may not be preserved anywhere else, and I will argue that gaining proper access to it will require a human presence. Moreover, while this will primarily be a task for the geosciences, I will argue that the astronomical and biological sciences would also benefit from a renewed human presence on the Moon, and especially from the establishment of a permanently occupied scientific outpost.

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Secular changes in the xenon and krypton abundances in the solar wind recorded in single lunar grains

Cited by 62 publications

References 16 publications

Nitrogen components in primitive ordinary chondrites

Nitrogen components in primitive ordinary chondrites

Noble gas space exposure ages of individual interplanetary dust particles

The scientific case for renewed human activities on the Moon

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