Organic compounds in the Forest Vale, H4 ordinary chondrite

Abstract-The successful return of the Stardust spacecraft provides a unique opportunity to investigate the nature and distribution of organic matter in cometary dust particles collected from comet 81P ⁄ Wild 2. Analysis of individual cometary impact tracks in silica aerogel using the technique of two-step laser mass spectrometry demonstrates the presence of complex aromatic organic matter. While concerns remain as to the organic purity of the aerogel collection medium and the thermal effects associated with hypervelocity capture, the majority of the observed organic species appear indigenous to the impacting particles and are hence of cometary origin.

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“…1992); [2] carbonaceous and ordinary chondrites (Hahn et al. 1988; Zenobi et al. 1989, 1992); [3] Martian meteorites (McKay et al.…”

Section: Experimental Technique and Sample Preparationmentioning

confidence: 99%

Complex aromatic hydrocarbons in Stardust samples collected from comet 81P/Wild 2

Clemett¹,

Sandford

Nakamura‐Messenger

et al. 2010

Meteorit & Planetary Scien

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“…The development of this device has also benefited greatly from the contributions of several postdoctoral research associates including F. Engelke, J.-M. Phillipoz, L. J. Kovalenko, and X. D. F. Chillier. The detailed applications of this instrument to the study of meteoritic samples may be found elsewhere Zenobi et al 1989Zenobi et al , 1992Kovalenko et al 1991Kovalenko et al , 1992Zenobi h Zare, 1991;Clemett et al 1993;Thomas et al 1995a;Maechling et al 1995;McKay et al 1996). In what follows we emphasize the capabilities of this analytic tool and its present limitations.…”

mentioning

confidence: 92%

Microprobe two-step laser mass spectrometry as an analytical tool for meteoritic samples

Clemett

Zare

1997

Symp. - Int. Astron. Union

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Abstract. Microprobe two-step laser mass spectrometry (/iL 2 MS) is a new mass spectrometric method in which the two essential steps of any mass spectrometric analysis, vaporization and ionization, are carried out using two independent laser sources. In the first step, the output of a pulsed infrared laser is focused on the sample to cause rapid heating in the spot area illuminated, which is typically 40 /zm by 40 /im. In the second step, the output of a pulsed ultraviolet laser causes (1+1) resonance-enhanced multiphoton ionization (REMPI) of those desorbed neutral molecules that (1) are able to absorb this UV wavelength and (2) whose ionization potential is less than the energy of two photons of this UV wavelength. The resulting ions are then mass analyzed in a reflectron time-of-flight apparatus. Under suitable conditions fragmentation can be avoided in both the vaporization and ionization steps so that μΙι 2 Μ8 can be applied to the analysis of a mixture of molecules. Applications of ^L 2 MS to meteorite samples are presented as a means of detecting trace amounts of certain organic molecules present in complex materials without prior sample preparation, extraction, purification, and separation steps. Moreover, this analysis can be carried out with micrometer spatial resolution so that in favorable cases the presence or absence of certain molecules can be correlated to mineralogical features of the sample.

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“…Given their history of thermal metamorphism, most carbon will have been devolatilised on the parent body or turned to kerogen or graphite. Nonetheless, Polycyclic Aromatic Hydrocarbons (PAH) and amino acids can still be found in small concentrations in ordinary chondrites (Zenobi et al, 1992). …”

Section: Discussionmentioning

confidence: 99%

Microbial Populations of Stony Meteorites: Substrate Controls on First Colonizers

et al. 2017

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Finding fresh, sterilized rocks provides ecologists with a clean slate to test ideas about first colonization and the evolution of soils de novo. Lava has been used previously in first colonizer studies due to the sterilizing heat required for its formation. However, fresh lava typically falls upon older volcanic successions of similar chemistry and modal mineral abundance. Given enough time, this results in the development of similar microbial communities in the newly erupted lava due to a lack of contrast between the new and old substrates. Meteorites, which are sterile when they fall to Earth, provide such contrast because their reduced and mafic chemistry commonly differs to the surfaces on which they land; thus allowing investigation of how community membership and structure respond to this new substrate over time. We conducted 16S rRNA gene analysis on meteorites and soil from the Nullarbor Plain, Australia. We found that the meteorites have low species richness and evenness compared to soil sampled from directly beneath each meteorite. Despite the meteorites being found kilometers apart, the community structure of each meteorite bore more similarity to those of other meteorites (of similar composition) than to the community structure of the soil on which it resided. Meteorites were dominated by sequences that affiliated with the Actinobacteria with the major Operational Taxonomic Unit (OTU) classified as Rubrobacter radiotolerans. Proteobacteria and Bacteroidetes were the next most abundant phyla. The soils were also dominated by Actinobacteria but to a lesser extent than the meteorites. We also found OTUs affiliated with iron/sulfur cycling organisms Geobacter spp. and Desulfovibrio spp. This is an important finding as meteorites contain abundant metal and sulfur for use as energy sources. These ecological findings demonstrate that the structure of the microbial community in these meteorites is controlled by the substrate, and will not reach homeostasis with the Nullarbor community, even after ca. 35,000 years. Our findings show that meteorites provide a unique, sterile substrate with which to test ideas relating to first-colonizers. Although meteorites are colonized by microorganisms, the microbial population is unlikely to match the community of the surrounding soil on which they fall.

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Organic compounds in the Forest Vale, H4 ordinary chondrite

Cited by 36 publications

References 23 publications

Complex aromatic hydrocarbons in Stardust samples collected from comet 81P/Wild 2

Complex aromatic hydrocarbons in Stardust samples collected from comet 81P/Wild 2

Microprobe two-step laser mass spectrometry as an analytical tool for meteoritic samples

Microbial Populations of Stony Meteorites: Substrate Controls on First Colonizers

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