N. Kinoshita, M. Paul, Y. Kashiv, P. Collon, C. M. Deibel, B. DiGiovine, J. P. Greene, D. J. Henderson, C. L. Jiang, S. T. Marley, T. Nakanishi, R. C. Pardo, K. E. Rehm, D. Robertson, R. Scott, C. Schmitt, X. D. Tang, R. Vondrasek, A. Yokoyama
The extinct p-process nuclide 146Sm serves as an astrophysical and
geochemical chronometer through measurements of isotopic anomalies of its
alpha-decay daughter 142Nd. We performed a new measurement of the 146Sm
half-life and our result, 68 \pm 9 (1sigma) million years (Ma), is
significantly shorter than the value currently used of 103 \pm 5 Ma, modifying
the early chronology of the Solar System and planetary differentiation. The new
half-life value implies a higher initial 146Sm abundance in the Early Solar
System, (146Sm/144Sm)_0 = 0.0094\pm0.0005 (2sigma), than derived so far.
Terrestrial, Lunar and Martian planetary silicate mantle differentiation events
dated by 146Sm-142Nd converge to a shorter time span and in general to earlier
times, due to the combined effect of the new 146Sm half-life and
(146Sm/144Sm)_0 values.
View original:
http://arxiv.org/abs/1109.4805
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