@article { , title = {Sulfur isotopic compositions of submicrometer SiC grains from the Murchison meteorite}, abstract = {We report C, Si, N, S, Mg-Al, and Ca-Ti isotopic compositions of presolar silicon carbide (SiC) grains from the SiC-rich KJE size fraction (0.5-0.8 μm) of the Murchison meteorite. One thousand one hundred thirteen SiC grains were identified based on their C and Si isotopic ratios. Mainstream, AB, C, X, Y, and Z subtypes of SiC, and X-type silicon nitride (Si₃N₄) account for 81.4\%, 5.7\%, 0.1\%, 1.5\%, 5.8\%, 4.9\%, and 0.4\%, respectively. Twenty-five grains with unusual Si isotopic ratios, including one C grain, 16 X grains, 1 Y grain, 5 Z grains, and 2 X-type Si₃N₄ grains were selected for N, S, Mg-Al, and Ca-Ti isotopic analysis. The C grain is highly enriched in ²⁹Si and ³⁰Si (δ²⁹Si = 1345‰ ± 19‰, δ³⁰Si = 1272‰ ± 19‰). It has a huge ³²S excess, larger than any seen before, and larger than that predicted for the Si/S supernova (SN) zone, providing evidence against the elemental fractionation model by Hoppe et al. Two SN models investigated here present a more satisfying explanation in terms of a radiogenic origin of ³²S from the decay of short-lived ³²Si (τ1/2 = 153 yr). Silicon-32 as well as ²⁹Si and ³⁰Si can be produced in SNe by short neutron bursts; evidence for initial 44Ti (τ1/2 = 60 yr) in the C grain is additional evidence for an SN origin. The X grains have marginal ³²S excesses, much smaller than expected from their large ²⁸Si excesses. Similarly, the Y and Z grains do not show the S-isotopic anomalies expected from their large Si isotopic anomalies. Low intrinsic S contents and contamination with isotopically normal S are the most likely explanations.}, doi = {10.1088/0004-637x/799/2/156}, eissn = {1538-4357}, issn = {0004-637X}, issue = {2}, journal = {Astrophysical journal}, pages = {156}, publicationstatus = {Published}, publisher = {American Astronomical Society}, url = {https://hull-repository.worktribe.com/output/383703}, volume = {799}, keyword = {Lasers and Light Matter Interactions, Specialist Research - Other, Astrochemistry, Circumstellar matter, Nuclear reactions, nucleosynthesis, abundances, Supernovae: general, Stars: AGB and post-AGB}, year = {2015}, author = {Xu, Yuchen and Zinner, Ernst and Gallino, Roberto and Heger, Alexander and Pignatari, Marco and Lin, Yangting} }