Origin of heterogeneous isotope distribution for heavy elements in the early solar system

我们研究了早期太阳系中重元素同位素不均匀分布的起源。利用TIMS对块体岩石中的钙钛矿和钙钛矿以及球粒陨石成分（例如，CAIs、球粒、酸沥滤物）。我们发现，行星尺度的同位素不均匀性只存在于50%冷凝温度在1300 K到1600 K之间的中等难熔元素（例如，Cr、Mo、Sr）。这意味着中等难熔元素的同位素不均匀性是由与星子形成之前的原行星盘中的热处理，材料运输和混合有关的尘埃颗粒的动力学历史产生的，而不是假设超新星注入和/或粒度分选等过程。

We have investigated the origin of heterogeneous isotope distribution for heavy elements in the early solar system. Highly precise isotope analyses of Sr, Nd, Te, and Mo were conducted using TIMS for bulk rocks of chondrites and nonchondrites, as well as for chondrite components (e.g., CAIs, chondrules, acid leachates). We found that planetary scale isotope heterogeneities exist only for moderately refractory elements with 50% condensation temperature between 1300K to 1600K (e.g., Cr, Mo, Sr). This implies that isotope heterogeneities for moderately refractory elements were created by a dynamical history of dust grains related to thermal processing, material transportation, and mixing in the protoplanetary disk prior to planetesimal formation, rather than assuming processes such as supernova injection and/or grain-size sorting.