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

我们研究了太阳前颗粒中富集的球粒酸残基的Os同位素组成。我们发现块状球粒陨石含有各种类型的前太阳相，富含s-过程o或r-过程o。富r工艺相可以在相对温和的酸性条件下从球粒陨石中提取，而富s工艺相则表现出很强的耐酸性。我们还发现一些富r过程相通过母体的水蚀作用被选择性地破坏。

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.