出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Presolar grains are considered to have traces in their birth before the solar system formation in
their isotopic and elemental features. Most of silicon carbide type X (SiC X) and low density
graphite grains show the excesses of 12C and 28Si. These isotopic features suggest that SiC X and
low density graphite are originating from supernovae. On the other hand, elemental signatures of
the grains suggest the grain formation in carbon-enriched materials, although the bulk composition
of supernova ejecta is oxygen-rich. Therefore, the parent materials of the grains should have
been formed by large-scale inhomogeneous mixing during supernova explosions to reproduce
isotopic elemental signatures of presolar grains from supernovae. We investigate supernova mixtures
reproducing isotopic ratios of individual single SiC X and low density graphite grains. We
consider seven-layer mixtures of supernova ejecta. We seek mixtures reproducing as many isotopic
ratios as possible of each of the grains. Then, the mixtures reproducing ve and six isotopic
ratios of SiC X grains and low density graphite grains are obtained, respectively. The mixtures
are classied into three groups based on reproduced isotopic ratios. The main component of the
mixtures is one of deep Ni-rich layer, outer He/C layer, and He/N layer. The C/O ratios of most
of the mixtures are larger than 1. The ratios of Fe/C and Fe/Si are different between the mixtures
corresponding to SiC X and low density graphite grains.
