High precision isotope analyses of presolar grains for the study of stellar nucleosynthesis

我们研究了富含在太阳前颗粒中的软骨酸残留物中的Os同位素组成。我们发现块状球粒陨石中含有多种类型的太阳系前相，富含S过程-Os或r-过程-O。球粒陨石中的r-过程富集相可以在相对温和的酸性条件下提取，而S过程富集相表现出较强的耐酸性。我们还发现，通过母体水蚀变选择性地破坏了一些r-过程富集相。

We have investigated Os isotope compositions in chondritic acid residues enriched in presolar grains. We found that bulk chondrites contain various types of presolar phases that are rich in either s-process-Os or r-process-Os. The r-process-enriched phases could be extracted from chondrites by a relatively mild acid condition, while s-process-enriched phases appeared to be highly acid resistant. We also found that some r-process-enriched phases were selectively destroyed via parent body aqueous alteration.