Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0356, USA.
Science. 2013 Oct 25;342(6157):463-6. doi: 10.1126/science.1242237.
Meteorites contain a wide range of oxygen isotopic compositions that are interpreted as heterogeneity in solar nebula. The anomalous oxygen isotopic compositions of refractory mineral phases may reflect a chemical fractionation process in the nebula, but there are no experiments to demonstrate this isotope effect during particle formation through gas-phase reactions. We report experimental results of gas-to-particle conversion during oxidation of silicon monoxide that define a mass-independent line (slope one) in oxygen three-isotope space of (18)O/(16)O versus (17)O/(16)O. This mass-independent chemical reaction is a potentially initiating step in nebular meteorite formation, which would be capable of producing silicate reservoirs with anomalous oxygen isotopic compositions.
陨石中含有广泛的氧同位素组成，这些组成被解释为太阳星云的不均匀性。难熔矿物相的异常氧同位素组成可能反映了星云中的化学分馏过程，但目前还没有实验证明在通过气相反应形成颗粒的过程中存在这种同位素效应。我们报告了一氧化硅氧化过程中气体到颗粒转化的实验结果，该结果在氧的三个同位素空间（18O/16O 对 17O/16O）中定义了一条质量独立线（斜率为 1）。这种质量独立的化学反应是行星形成过程中潜在的起始步骤，它能够产生具有异常氧同位素组成的硅酸盐储层。
