A Shorter Sm-146 Half-Life Measured and Implications for Sm-146-Nd-142 Chronology in the Solar System

作者：Kinoshita N; Paul M^*; Kashiv Y; Collon P; Deibel C M; DiGiovine B; Greene J P; Henderson D J; Jiang C L; Marley S T; Nakanishi T; Pardo R C; Rehm K E; Robertson D; Scott R; Schmitt C; Tang X D; Vondrasek R; Yokoyama A

来源：Science, 2012, 335(6076): 1614-1617.

DOI：10.1126/science.1215510

The extinct p-process nuclide Sm-146 serves as an astrophysical and geochemical chronometer through measurements of isotopic anomalies of its alpha-decay daughter Nd-142. Based on analyses of Sm-146/Sm-147 alpha-activity and atom ratios, we determined the half-life of Sm-146 to be 68 +/- 7 (1 sigma) million years, which is shorter than the currently used value of 103 +/- 5 million years. This half-life value implies a higher initial Sm-146 abundance in the early solar system, (Sm-146/Sm-144)(0) = 0.0094 +/- 0.0005 (2 sigma), than previously estimated. Terrestrial, lunar, and martian planetary silicate mantle differentiation events dated with Sm-146-Nd-142 converge to a shorter time span and in general to earlier times, due to the combined effect of the new Sm-146 half-life and (Sm-146/Sm-144)(0) values.

• 出版日期2012-3-30