TY - JOUR
T1 - Shorter half-life of p-process 146Sm measured and 146Sm/142Nd chronology of the Solar System
AU - Kinoshita, N.
AU - Paul, M.
AU - Kashiv, Y.
AU - Collon, P.
AU - Robertson, D.
AU - Schmitt, C.
AU - Tang, X. D.
AU - DiGiovine, B.
AU - Greene, J. P.
AU - Henderson, D. J.
AU - Jiang, C. L.
AU - Marley, S. T.
AU - Pardo, R. C.
AU - Rehm, K. E.
AU - Scott, R.
AU - Vondrasek, R.
AU - Deibel, C.
AU - Nakanishi, T.
AU - Yokoyama, A.
PY - 2012
Y1 - 2012
N2 - The short-lived nuclide 146Sm, synthesized in stellar events by the p-process and now extinct in the Solar System, serves as both an astrophysical and geochemical chronometer through measurements of isotopic anomalies of its α-decay daughter 142Nd. Using artificially produced 146Sm via 147Sm(γ,n), 147Sm(n, 2n) and 147Sm(p,nε) reactions, we performed a new measurement of the 146Sm half-life by measuring the 146Sm/ 147Sm alpha activity with a Si surface barrier detector and the 146Sm/147Sm atom ratio with accelerator mass spectrometry (AMS). Our result, t114/ 62 = 68 ± 7 (1σ) million years (My), is significantly shorter than the adopted value (103 ± 5 My). The shorter 146Sm half-life value implies a higher initial Solar System ratio, (146Sm/144Sm)0 = 0.0094 ± 0.0005 (2σ), than the recently derived value 0.0085 ± 0.0007(2σ). The time interval between isolation of the Solar Nebula from the interstellar medium and formation of the first solids, is reduced by a factor of ∼2.5 to 20 from previous estimates. Early planetary mantle differentiation processes on Earth, the Moon and Mars dated by 146Sm-142Nd converge to a shorter time span, due to the combined effect of the new 146Sm half-life and (146Sm/144Sm)0 values.
AB - The short-lived nuclide 146Sm, synthesized in stellar events by the p-process and now extinct in the Solar System, serves as both an astrophysical and geochemical chronometer through measurements of isotopic anomalies of its α-decay daughter 142Nd. Using artificially produced 146Sm via 147Sm(γ,n), 147Sm(n, 2n) and 147Sm(p,nε) reactions, we performed a new measurement of the 146Sm half-life by measuring the 146Sm/ 147Sm alpha activity with a Si surface barrier detector and the 146Sm/147Sm atom ratio with accelerator mass spectrometry (AMS). Our result, t114/ 62 = 68 ± 7 (1σ) million years (My), is significantly shorter than the adopted value (103 ± 5 My). The shorter 146Sm half-life value implies a higher initial Solar System ratio, (146Sm/144Sm)0 = 0.0094 ± 0.0005 (2σ), than the recently derived value 0.0085 ± 0.0007(2σ). The time interval between isolation of the Solar Nebula from the interstellar medium and formation of the first solids, is reduced by a factor of ∼2.5 to 20 from previous estimates. Early planetary mantle differentiation processes on Earth, the Moon and Mars dated by 146Sm-142Nd converge to a shorter time span, due to the combined effect of the new 146Sm half-life and (146Sm/144Sm)0 values.
UR - http://www.scopus.com/inward/record.url?scp=84887488962&partnerID=8YFLogxK
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AN - SCOPUS:84887488962
SN - 1824-8039
JO - Proceedings of Science
JF - Proceedings of Science
T2 - 12th International Symposium on Nuclei in the Cosmos, NIC 2012
Y2 - 5 August 2012 through 12 August 2012
ER -