Bizzarro Martin, Ulfbeck David, Trinquier Anne, Thrane Kristine, Connelly James N, Meyer Bradley S
Geological Institute, University of Copenhagen, Øster Voldgade 10, DK-1350, Denmark.
Science. 2007 May 25;316(5828):1178-81. doi: 10.1126/science.1141040.
High-precision 60Fe-60Ni isotope data show that most meteorites originating from differentiated planetesimals that accreted within 1 million years of the solar system's formation have 60Ni/58Ni ratios that are approximately 25 parts per million lower than samples from Earth, Mars, and chondrite parent bodies. This difference indicates that the oldest solar system planetesimals formed in the absence of 60Fe. Evidence for live 60Fe in younger objects suggests that 60Fe was injected into the protoplanetary disk approximately 1 million years after solar system formation, when 26Al was already homogeneously distributed. Decoupling the first appearance of 26Al and 60Fe constrains the environment where the Sun's formation could have taken place, indicating that it occurred in a dense stellar cluster in association with numerous massive stars.
高精度的60Fe-60Ni同位素数据表明，大多数源自太阳系形成后100万年内吸积的分异小行星的陨石，其60Ni/58Ni比值比来自地球、火星和球粒陨石母体的样本低约百万分之25。这种差异表明，最古老的太阳系小行星是在没有60Fe的情况下形成的。较年轻天体中存在活60Fe的证据表明，60Fe在太阳系形成后约100万年被注入原行星盘，此时26Al已经均匀分布。26Al和60Fe首次出现的解耦限制了太阳形成可能发生的环境，表明它发生在一个与众多大质量恒星相关的致密星团中。
