标题： 原始陨石中主流SiC颗粒的硅和钛同位素组成的一个新的天体物理学解释 显示英文标题

标题： A New Astrophysical Interpretation of the Si and Ti Isotopic Compositions of Mainstream SiC Grains from Primitive Meteorites

摘要： 原始陨石中的主流前太阳SiC颗粒在重微量元素的同位素组成上显示出明显的s-过程特征。这些颗粒很可能在各种AGB星风中凝结而成。然而，这些颗粒中测量到的非太阳和相关的硅与钛同位素组成与纯s-特征不符。我们通过假设母AGB星的原始成分存在差异来解决这个备受关注的问题，这种差异是由于它们诞生时星际介质中的小化学不均一性造成的。这些不均一性可能自然地源于超新星II型（SNII）和不同子类型的Ia型超新星（SNIa）相关恒星核合成场所对星际介质中每种同位素贡献的变化。 显示英文摘要

摘要： Mainstream presolar SiC grains from primitive meteorites show a clear s-process signature in the isotopic composition of heavy trace elements. These grains most likely condensed in the winds of a variety of AGB stars. However, the non-solar and correlated Si and Ti isotopic compositions measured in these grains are inconsistent with a pure s-signature. We present a possible solution to this much-discussed problem by assuming a spread in the original composition of parent AGB stars due to small chemical inhomogeneities in the interstellar medium at the time of their birth. These inhomogeneities may naturally arise from variations in the contributions of each nuclide to the interstellar medium by the relevant stellar nucleosynthetic sites, SNII and different subtypes of SNIa.