Coordinated EDX and micro-Raman analysis of presolar silicon carbide: A novel, nondestructive method to identify rare subgroup SiC
Replaced (7 August 2020) by:
Coordinated EDX and micro‐Raman analysis of presolar silicon carbide: A novel, nondestructive method to identify rare subgroup SiC
Nan Liu, Andrew Steele, Larry R. Nittler, Rhonda M. Stroud, Bradley T. De Gregorio, Conel M. O’D. Alexander, Jianhua Wang
Meteoritics & Planetary Science
Version of Record online:07 August 2020
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“We noticed a few minor errors in Table S2 in the supplement of the original manuscript, as summarized below. (1) The error for the 14N/15N ratio of grain M2‐A4‐G27 should be 0.2 instead of 0.3. (2) The δ30Si value of grain M1‐A5‐G1112 should be 16 instead of 19. (3) The names of grains M2‐A1‐G569 and M2‐A1‐G576 should be M2‐A2‐G569 and M2‐A1‐G576‐2, respectively. This erratum contains the correct data table (Table S2).
In addition, we would like to note that the isotope ratios for grains M1‐A4‐G557 and M2‐A1‐G303 reported in Table S2 are slightly different from those reported in Liu et al. (2017), due to small differences in the adopted regions of interest (ROIs) for data reduction. The use of different ROIs and slightly different normalization approaches also resulted in small differences between the silicon isotope ratios of X grains reported in Table S2 and in Liu et al. (2018). The two sets of data, however, generally overlap with each other within 1σ errors, and the small differences do not affect any of the discussions or conclusions in these papers.”
Original paper:
Coordinated EDX and micro-Raman analysis of presolar silicon carbide: A novel, nondestructive method to identify rare subgroup SiC
Liu, N., Steele, A., Nittler, L. R., Stroud, R. M., De Gregorio, B. T., Alexander, C. M. O’D. and Wang, J.
Meteoritics & Planetary Science. doi: 10.1111/maps.12954
“We report the development of a novel method to nondestructively identify presolar silicon carbide (SiC) grains with high initial 26Al/27Al ratios (>0.01) and extreme 13C-enrichments (12C/13C ≤ 10) by backscattered electron-energy dispersive X-ray (EDX) and micro-Raman analyses. Our survey of a large number of presolar SiC demonstrates that (1) ~80% of core-collapse supernova and putative nova SiC can be identified by quantitative EDX and Raman analyses with >70% confidence; (2) ~90% of presolar SiC are predominantly 3C-SiC, as indicated by their Raman transverse optical (TO) peak position and width; (3) presolar 3C-SiC with 12C/13C ≤ 10 show lower Raman TO phonon frequencies compared to mainstream 3C-SiC. The downward shifted phonon frequencies of the 13C-enriched SiC with concomitant peak broadening are a natural consequence of isotope substitution. 13C-enriched SiC can therefore be identified by micro-Raman analysis; (4) larger shifts in the Raman TO peak position and width indicate deviations from the ideal 3C structure, including rare polytypes. Coordinated transmission electron microscopy analysis of one X and one mainstream SiC grain found them to be of 6H and 15R polytypes, respectively; (5) our correlated Raman and NanoSIMS study of mainstream SiC shows that high nitrogen content is a dominant factor in causing mainstream SiC Raman peak broadening without significant peak shifts; and (6) we found that the SiC condensation conditions in different stellar sites are astonishingly similar, except for X grains, which often condensed more rapidly and at higher atmospheric densities and temperatures, resulting in a higher fraction of grains with much downward shifted and broadened Raman TO peaks”
