Verchovsky, Alexander B. and Fisenko, Anatolii V. and Semjonova, Lubov F. and Bridges, John and Lee, Martin R. and Wright, Ian P. (2006) Nanodiamonds from AGB Stars: A New Type of Presolar Grain in Meteorites. The Astrophysical Journal, 651 (1). pp. 481-490.
Full text is not hosted in this archive but may be available via the Official URL, or by requesting a copy from the corresponding author.
Official URL: http://stacks.iop.org/0004-637X/651/481
Although the most abundant type of presolar grain found in meteorites is nanometer-sized diamond ("nanodiamond"), the dimensions make study of individual crystallites rather uninformative; instead, laboratory astrophysicists usually work with an ensemble of grains (generally in concentrated form, produced by chemical treatments). This, of course, produces results that are just a measure of average properties, which makes assessing the origin of diamonds quite difficult. An apparently uniform distribution of chemical and physical properties of the grains has been interpreted as their having a single origin. In this paper, however, we demonstrate that slight variations in average grain size can be exploited, using differential centrifugation (followed by analysis using electron microscopy and isotope-ratio mass spectrometry), to produce separates that reflect contributions from specific sources. In this way we identify a contribution from carbon stars, at the asymptotic giant branch stage of evolution, in addition to components already ascribed to supernovae and solar nebular processing. The astrophysical significance of the new discovery is discussed.
|Deposited By:||Prof. Alexey Ivanov|
|Deposited On:||06 Feb 2010 11:10|
|Last Modified:||06 Feb 2010 11:53|
Repository Staff Only: item control page