Trace element abundances in single presolar silicon carbide grains by synchrotron X-ray fluorescence

Details Trace element abundances in single presolar silicon carbide grains by synchrotron X-ray fluorescence Trace element abundances in single presolar silicon carbide grains by synchrotron X-ray fluorescence

Dec 2004

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004phdt.......199k&link_type=abstract

Thesis (PhD). THE UNIVERSITY OF CHICAGO, Source DAI-B 65/06, p. 2967, Dec 2004, 206 pages.

Computer Science

3

Scientific paper

Synchrotron x-ray fluorescence (SXRF) was applied to the study of presolar grains for the first time in this study. 41 single SiC grains of the KJF size fraction (mass-weighted median size of 1.86 μm) from the Murchison (CM2) Meteorite were analyzed. The absolute abundances of the following elements were determined (not every element in every grain): S, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Sr, Y, Zr, Nb, Mo, Ru, Os, Ir and Pt (underlined elements were detected here for the first time in single grains). There is good agreement between the heavier trace element abundances in the grains and s-process nucleosynthesis calculations. It suggests that smaller 13C pocket sizes are needed in the parent stars, a free parameter in the stellar models, than is deduced from isotopic analyses of s-, and s-mainly, elements, such as Zr and Mo. In addition, the data confirms the radiogenic nature of the Nb in the grains, due to the in situ decay of 93Zr (t 1/2 = 1.5 × 106 year). The data suggest that the trace elements condensed into the host SiC grains by a combination of condensation in solid solution and incorporation of subgrains. It seems that many of the trace elements reside mainly in subgrains of two solid solution: (1)a TiC based solid solution, and (2)a Mo-Ru carbide based solid solution. The presence of subgrains of an Fe-Ni alloy solid solution is suggested as well. Subgrains of all 3 solid solutions were observed previously in presolar graphite grains.* *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Adobe Acrobat.

Affiliated with

Also associated with

No associations

Rating

Trace element abundances in single presolar silicon carbide grains by synchrotron X-ray fluorescence does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Trace element abundances in single presolar silicon carbide grains by synchrotron X-ray fluorescence, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Trace element abundances in single presolar silicon carbide grains by synchrotron X-ray fluorescence will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1164164