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presolar grains; isotopic compositions; ion microprobe mass spectrometry
Abstract:
Primitive meteorites contain small quantities of presolar grains with highly anomalous isotopic compositions. These grains formed in stellar atmospheres or in the ejecta of stellar explosions and they represent a sample of stardust that can be analyzed with high precision in the laboratory. Such studies provide a wealth of information on many aspects related to nuclear astrophysics. The ion microprobe mass spectrometry allows to measure isotopic compositions of a large number of elements in single presolar dust grains. Currently-used instrumentation is limited to the study of grains with sizes >0.5 mum. The new generation NanoSIMS 50 ion microprobe will allow to extend isotopic studies to considerably smaller scales. This instrument was recently installed at Washington University in St. Louis and at the Max-Planck-Institute for Chemistry in Mainz, and considerable progress can be expected in the laboratory study of stardust in the next years. (C) 2002 Elsevier Science B.V. All rights reserved.
