Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA.
International Center for Planetary Science, College of Earth Sciences, Chengdu University of Technology, 610059 Chengdu, China.
Science. 2023 Jan 27;379(6630):372-376. doi: 10.1126/science.abn1783. Epub 2023 Jan 26.
Meteorites record processes that occurred before and during the formation of the Solar System in the form of nucleosynthetic anomalies: isotopic compositions that differ from the Solar System patterns. Nucleosynthetic anomalies are rarely seen in volatile elements such as potassium at bulk meteorite scale. We measured potassium isotope ratios in 32 meteorites and identified nucleosynthetic anomalies in the isotope potassium-40. The anomalies are larger and more variable in carbonaceous chondrite (CC) meteorites than in noncarbonaceous (NC) meteorites, indicating that CCs inherited more material produced in supernova nucleosynthesis. The potassium-40 anomaly of Earth is close to that of the NCs, implying that Earth's potassium was mostly delivered by NCs.
同位素组成与太阳系模式不同。在挥发性元素（如整体陨石规模的钾）中很少见到核合成异常。我们测量了 32 颗陨石中的钾同位素比值，并在同位素钾-40 中鉴定出核合成异常。在碳质球粒陨石（CC）中，异常比非碳质（NC）陨石更大且更具变异性，表明 CC 继承了更多在超新星核合成中产生的物质。地球的钾-40 异常接近 NCs，这意味着地球的钾主要由 NCs 提供。
