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Volumn 281, Issue 5380, 1998, Pages 1165-1168

C, N, and noble gas isotopes in grain size separates of presolar diamonds from Efremovka

Author keywords

[No Author keywords available]

Indexed keywords

CARBON; DIAMOND; INERT GAS; ISOTOPE; NITROGEN;

EID: 0032555521     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.281.5380.1165     Document Type: Article
Times cited : (73)

References (33)
  • 14
    • 0026274326 scopus 로고
    • _, Science 254, 1188 (1991).
    • (1991) Science , vol.254 , pp. 1188
  • 17
    • 3543018006 scopus 로고    scopus 로고
    • note
    • For TEM we used a Philips Biotwin instrument operated at 120 kV and a Topcon EM-002B operated at 200 kV.
  • 23
    • 3543006650 scopus 로고    scopus 로고
    • note
    • 13C = -32.7 per mil), also has considerably higher total and lower pyrolysis carbon yields. Apart from that, these data are also in agreement with ED-9 being the coarsest fraction.
  • 25
    • 3543010275 scopus 로고    scopus 로고
    • note
    • When considering N and noble gas abundances released by stepped combustion, it is necessary to normalize the yields of these species to the overall C content of each sample. This has been done for each step of the four extractions, and the results are presented as element-to-C ratios versus proportion of total C removed (Fig. 3).
  • 26
    • 3542996950 scopus 로고    scopus 로고
    • note
    • We cannot exclude the possibility that the primary ion energies could be modified because of ion collisions with dust particles and gas, present along with diamonds in the place where implantation has occurred, making the ion energies just enough to stop within diamond grains.
  • 27
    • 3543045660 scopus 로고    scopus 로고
    • note
    • 36Ar ratios decrease with increasing grain size). This is clearly not compatible with preferential noble gas losses from smaller grains (as may accompany postformational heating, for instance) but is in agreement with an implantation mechanism at which small, light ions have a shorter projected range (31).
  • 29
    • 3543012658 scopus 로고    scopus 로고
    • note
    • 14N would be required at the same time, and that is not predicted in any of the supernova shells (32).
  • 33
    • 3543046245 scopus 로고    scopus 로고
    • note
    • Supported by the Particle Physics and Astronomy Research Council and by Russian Foundation of Basic Science grant 96-05-64546 (A.V.F. and L.F.S.). We thank J. Findlay and J. R. Fryer for assistance with TEM.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.