The Formation of Graphite Whiskers in the Primitive Solar Nebula

Nuth, Joseph A.; Kimura, Yuki; Lucas, C. A.; Ferguson, Frank T.; Johnson, Natasha M.

doi:10.1088/2041-8205/710/1/l98

Cited by 15 publications

(31 citation statements)

References 16 publications

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“…has recently shown that any solid surface can promote Fischer‐Tropsch Type (FTT) reactions, even graphite (Nuth et al. ). A more interesting finding is that the FTT reactions appear to leave an organic film on the grain surface that is a more effective catalyst than the original material, thus greatly increasing the efficiency of FTT reactions in converting CO and H 2 into organic materials.…”

Section: Discussionmentioning

confidence: 99%

Can lightning produce significant levels of mass‐independent oxygen isotopic fractionation in nebular dust?

Nuth

Paquette

Farquhar

2012

Meteorit & Planetary Scien

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Abstract-Based on recent evidence that oxide grains condensed from a plasma will contain oxygen that is mass-independently fractionated compared to the initial composition of the vapor, we present a first attempt to evaluate the potential magnitude of this effect on dust in the primitive solar nebula. This assessment relies on previous studies of nebular lightning to provide reasonable ranges of physical parameters to form a very simple model to evaluate the plausibility that lightning could affect a significant fraction of nebular dust and that such effects could cause a significant change in the oxygen isotopic composition of solids in the solar nebula over time. If only a small fraction of the accretion energy is dissipated as lightning over the volume of the inner solar nebula, then a large fraction of nebular dust will be exposed to lightning. If the temperature of such bolts is a few percent of the temperatures measured in terrestrial discharges, then dust will vaporize and recondense in an ionized environment. Finally, if only a small average decrease is assumed in the 16 O content of freshly condensed dust, then over the last 5 Myr of nebular accretion the average D 17 O of the dust could increase by more than 30 per mil. We conclude that it is possible that the measured "slope 1" oxygen isotope line measured in meteorites and their components represents a time-evolution sequence of nebular dust over the last several million years of nebular evolution where 16 O-rich materials formed first, then escaped further processing as the average isotopic composition of the dust gradually became increasingly depleted in 16 O.

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Section: Discussionmentioning

confidence: 99%

Can lightning produce significant levels of mass‐independent oxygen isotopic fractionation in nebular dust?

Nuth

Paquette

Farquhar

2012

Meteorit & Planetary Scien

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“…In a more recent work Nuth & Johnson (2010) studied the reactions of CO and H 2 on graphite surfaces and showed that this can lead to the formation of carbon nano-tubes at temperatures as low as 873 K. Apparently, graphite surfaces can also be efficient catalysts in the formation of species of astrophysical interest, such as carbon nano-tubes.…”

Section: Carbon Grainsmentioning

confidence: 99%

“…The Fischer-Tropsch type synthesis of carbonaceous materials is a process that appears to work within the inner nebula. The products of this reaction could clearly also be carried from the inner nebula and out to the Kuiper Belt and possibly beyond (e.g., Nuth & Johnson 2010). From these mass transfer circulation patterns, and the effects of (proto-)stellar jets, both carbon dust and crystalline and amorphous silicates, could have been formed or processed in the inner nebulae and transported out to the edge of the solar system, possibly to be lost via the processes that eventually clear out these nebular regions, e.g., T Tauri winds.…”

Section: The Effects Of Stars and Star Formation Re-examinedmentioning

confidence: 99%

Dust destruction in the ISM: a re-evaluation of dust lifetimes

Jones

Nuth

2011

A&A

206

224

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Context. There is a long-standing conundrum in interstellar dust studies relating to the discrepancy between the time-scales for dust formation from evolved stars and the apparently more rapid destruction in supernova-generated shock waves. Aims. We re-examine some of the key issues relating to dust evolution and processing in the interstellar medium. Methods. We use recent and new constraints from observations, experiments, modelling and theory to re-evaluate dust formation in the interstellar medium (ISM). Results. We find that the discrepancy between the dust formation and destruction time-scales may not be as significant as has previously been assumed because of the very large uncertainties involved. Conclusions. The derived silicate dust lifetime could be compatible with its injection time-scale, given the inherent uncertainties in the dust lifetime calculation. The apparent need to re-form significant quantities of silicate dust in the tenuous interstellar medium may therefore not be a strong requirement. Carbonaceous matter, on the other hand, appears to be rapidly recycled in the ISM and, in contrast to silicates, there are viable mechanisms for its re-formation in the ISM.

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“…In addition, it has been proposed they can form in protostellar nebulae via Fischer-Tropsch-type catalytic reactions [61,62]. Recent experiments by the same group investigating the potential of Fischer-Tropsch and Haber-Bosch type reactions appear to support this hypothesis [63]. Thus, it is the collective data from both ex situ and in situ examinations that are important; however, the limitations of each implemented technique, and the specifics of the synthesis route in question must be considered as there is no single universal growth mode.…”

Section: Growth Mechanismsmentioning

confidence: 99%

Synthesis of carbon nanotubes with and without catalyst particles

et al. 2011

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The initial development of carbon nanotube synthesis revolved heavily around the use of 3d valence transition metals such as Fe, Ni, and Co. More recently, noble metals (e.g. Au) and poor metals (e.g. In, Pb) have been shown to also yield carbon nanotubes. In addition, various ceramics and semiconductors can serve as catalytic particles suitable for tube formation and in some cases hybrid metal/metal oxide systems are possible. All-carbon systems for carbon nanotube growth without any catalytic particles have also been demonstrated. These different growth systems are briefly examined in this article and serve to highlight the breadth of avenues available for carbon nanotube synthesis.

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The Formation of Graphite Whiskers in the Primitive Solar Nebula

Cited by 15 publications

References 16 publications

Can lightning produce significant levels of mass‐independent oxygen isotopic fractionation in nebular dust?

Can lightning produce significant levels of mass‐independent oxygen isotopic fractionation in nebular dust?

Dust destruction in the ISM: a re-evaluation of dust lifetimes

Synthesis of carbon nanotubes with and without catalyst particles

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