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Assuming that similar organic components as in comet 81P/Wild 2 are present in incoming meteoroids, we try to anticipate the observable signatures they would produce for meteor detection techniques. In this analysis we consider the elemental and organic components in cometary aggregate interplanetary dust particles and laboratory analyses of inter- and circumstellar carbon dust analogues. On the basis of our analysis we submit that (semi) quantitative measurements of H, N and C produced during meteor ablation will open an entire new aspect to using meteoroids as tracers of these volatile element abundances in active comets and their contributions to the mesospheric metal layers. [ABSTRACT FROM AUTHOR]

Bulk compositions of aggregate meteoroids made of the originally accreted dust with its highly varied in mineral content and chemistry and considerable grain size variations do not have a chondritic bulk composition. Deviations from CI element abundances reflect indigenous variations within and among comet nuclei. These unmodified meteoroids that are heterogeneous in all their properties are fundamentally different from meteoroids with a CI bulk composition that are fine-grained, equigranular materials and chemically and mineralogically homogeneous. Collection and data reduction bias exists but the compositions of individual fast meteors are entirely constrained by the measured main component meteor abundances. [ABSTRACT FROM AUTHOR]

We describe the extraction methodologies for the isolation of fullerenes in synthetic "Graphitic Smokes" soot. These same methods were used to isolate natural fullerenes in some carbonaceous chondrite meteorites and in meteor impact-related sedimentary deposits previously described in the literature. In addition, a new functionalizatoin methodology that significantly enhances the yield of fullerenes extracted in synthetic fullerene material (up to 20% fullerene) will be discussed. Both laser desorption-mass spectrometry and high-resolution transmission electron microscopy were used to characterize fullerenes extracted from the synthetic soot. These extraction methods promise to reveal new insights on the encapsulaton of noble gases in a variety of fullerene and fullerene-related structures up to C1000. [ABSTRACT FROM AUTHOR]

Highly variable concentrations of natural C60 are reported from several coals from mines in the Yunnan-Guizhou provinces and the Inner Mongolia-Shanxi- Xinjiang provinces of China. The fullerene-extraction procedures from coals and C60 identification by Fourier Transform Infrared spectroscopy are described. [ABSTRACT FROM AUTHOR]

This paper presents the hypothesis that algal remains were precursors of the fullerenes in the hard carbonaceous rock Shungite (Russia), in carbonaceous matter from the hard rocks of the Black Member of the Onaping Formation at Sudbury (Canada), and in solid, hard bitumens from Mitov (Czech Republic). The paper argues further that PAHs from the biogenic matter were transformed, perhaps by cyclomerization followed by zip-up, during the geologic metamorphic stages experienced by these rocks. [ABSTRACT FROM AUTHOR]

A graptolitic shale, a metamorphosed black schist and a bituminous coal with different organic carbon content but without detectable amounts of fullerenes were subjected to high-energy electric impulses of current amplitudes comparable to those of natural lightning strikes that could lead to the formation of fulgurites. The search for fullerenes concentrated on rock surfaces altered during the impulse experiment using Fourier transform infrared spectroscopy (FTIR). Toluene-extractable materials from the altered zones were investigated by high-performance liquid chromatography (HPLC) and electron-impact ionization mass spectroscopy (EIMS). Powders from altered surfaces were also analyzed by laser desorption time-of-flight mass spectroscopy. Two of four characteristic C60 FTIR peaks were only observed in one piece of black schist. As no C60 fullerene was detected by HPLC and EIMS in this modified sample, we find no evidence that electric impulse-induced fullerenes were present in any samples. We discuss how the physicochemical conditions in our lightning-strike simulation experiments could have contributed to failure to produce fullerenes in rocks that are rich in organic carbon. Our results underscore the apparent paucity of natural fullerenes induced by lightning strikes. [ABSTRACT FROM AUTHOR]

Fullerene C60 occurs at extremely low concentration (0.2—0.3 ppm) in hard solid bitumen that was accumulated in the pillow lava bodies exposed at Mítov (Teplá-Barrandian Neo-proterozoic of the Bohemian Massif). No higher fullerenes were documented. The C60 fullerene and its precursors are present in non-graphitic and non-graphitizable carbonaceous matter. Inclusions of fullerene are found embedded within glass-like carbons that are found within the pillow lava bodies. Rare fullerenes in Mítov were probably preserved in the closed micropores and mesopores of the glass-like, solid bitumen. Pyrolysis of biogenic PAHs precursors seems a plausible way to form fullerenes in geological environments. [ABSTRACT FROM AUTHOR]

Fullerenes C60 and C70 were found in the thin clay seams of nine worldwide locations of the geologic boundary between the Cretaceous and Tertiary periods. These clays are also rich in soot. One hypothesis suggests that the fullerenes were synthesized in global wildfires that followed the meteorite impact 65 Ma ago. An alternative hypothesis suggests that the fullerenes predate the formation of the solar system because they contain isotopically anomalous helium in their carbon cages. [ABSTRACT FROM AUTHOR]

Reports concerning the presence or absence of fullerenes in chondritic meteorites are reviewed. Structural forms of carbonaceous matter in these meteorites are discussed in the context of fullerene formation. [ABSTRACT FROM AUTHOR]

If fullerenes are a common carbon phase in circumstellar dust and the presolar dust of the dense molecular wherein our solar system had formed, they should be present in the most primitive samples that still contain the vestiges of the accreting dust in the solar nebula 4.56 Ga ago. Such dust would be expected to have survived in comet nuclei and in the most primitive asteroids. They would be represented by collected chondritic, aggregate, interplanetary dust particles. As yet, there is no evidence of fullerenes in these particles but C60 and higher fullerenes are present in several carbonaceous chondrite meteorites. Metastable fullerenes may not survive the complex natural processing of comet and asteroid debris in the parent body, during solar system sojourn and atmospheric entry and laboratory storage. The possibility of fullerene modification to nanodiamonds in primitive asteroids is discussed. [ABSTRACT FROM AUTHOR]

We address the hypothesis that fullerenes are an important carrier phase for noble gases in carbonaceous chondrite meteorites. Unlike other proposed carbon carriers, nanodiamond, SiC, graphite and phase Q, fullerenes are extractable in an organic solvent. It is this unique property, in fact, this may be why fullerene molecules or fullerene-related compounds were overlooked as a carrier phase of noble gases in meteorites. To further evaluate how fullerenes trap noble gases within their closed-cage structure, we compared the natural meteorite fullerenes to synthetic "Graphitic Smokes" soot. High Resolution Transmission Electron Microscopy used to directly image the fullerene extracted residues clearly showed that C60 and higher fullerenes, predominantly C > 100, are indeed the carrier phase of the noble gases measured in the Tagish Lake, Murchison and Allende carbonaceous chondrite meteorites, and synthetic "Graphitic Smokes" material. The implication for the role of fullerenes, which trap noble gases condensed in the atmosphere of carbon-rich stars, is that the true nature of terrestrial planetary atmospheres is presolar in origin. Fullerene, like other carbon carriers, were then transported to the solar nebula, accreted into carbonaceous chondrites and delivered to the terrestrial planets. [ABSTRACT FROM AUTHOR]

Fullerene was theoretically predicted and experimentally discovered, but its detection in laboratory studies is still underrepresented with respect to its theoretical abundance. Recent High Resolution Transmission Electron Microscopy (HRTEM) studies of soot samples, however, lead to single fullerene molecule detection in higher amounts than was previously established. HRTEM is able to identify fullerenes even if they are only present in small quantities that would be below the detection limit of chemical techniques. Fullerenes will probably remain largely undetected until higher signal to noise ratio measurements are used to search for them. Such studies could yield different conclusions on fullerene abundances both in terrestrial and in extraterrestrial samples. For the latter, important astrophysical implications have to be considered. [ABSTRACT FROM AUTHOR]

The prediction of the existence of the fullerene C60 and its subsequent isolation from soot produced a large interest for fullerenes in the astronomical community. Fullerenes of astronomical origin have only been detected in meteorites and associated with an impact crater on the Long Duration Exposure Facility spacecraft. The discovery of fullerenes led to the hypothesis that they may be stable carbon molecules present in interstellar space. Many authors have suggested the possible presence of C60 and carbon onions in astrophysical environments as well as their relation to the diffuse interstellar bands (DIBs) and the UV bump at 220 nm in the interstellar extinction curve. As first evidence for the largest molecule ever detected in space, two diffuse interstellar bands (DIBs) have been identified in the near infrared that are consistent with laboratory measurements of the C60 cation. We review the current knowledge on fullerenes in space and present new observations of the interstellar bands at 957.7 nm and 963.2 nm. [ABSTRACT FROM AUTHOR]

A carbonaceous material formed from a hydrocarbon plasma called quenched carbonaceous composite (QCC) is shown to have functional groups that approximate the positions of the interstellar 217.5 nm absorption and the infrared emission features at 3.3—11.3 μm. A form of this material, called "dark-QCC" has abundant carbonaceous onion-like particles. We present the results of various experiments involving QCC and conjecture that the carbonaceous onion-like particles in QCC may be a good laboratory analog to the carrier of the interstellar absorption and emission features. A scenario for dust formation from carbonaceous onion-like particles is presented. [ABSTRACT FROM AUTHOR]

To gain information on fullerene formation, the production methods based on the evaporation of graphite are outlined. In particular, the effects of the buffer gas temperature are considered in connection with experiments performed with a laser furnace arrangement. In addition, fullerene formation by incomplete combustion and by pyrolysis is discussed. The former method is presently applied for large-scale fullerene production and very likely is also the source of most of the fullerenes occurring on earth. The formation processes based on evaporation and on combustion seem to be vastly different indicating that various chemical reaction routes lead to fullerenes. [ABSTRACT FROM AUTHOR]

This paper discusses measured textures, porosity, chemical compositions and the minerals of interplanetary dust and meteorites from primitive planetesimals and how this information can be used to explain some of the observed physical and chemical properties of meteor phenomena. [ABSTRACT FROM AUTHOR]