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Originally published in Science Express on 5 October 2006
Science 3 November 2006:
Vol. 314. no. 5800, pp. 806 - 809
DOI: 10.1126/science.1131708
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Reports

Solar Nebula Heterogeneity in p-Process Samarium and Neodymium Isotopes

Rasmus Andreasen and Mukul Sharma*

Bulk carbonaceous chondrites display a deficit of ~100 parts per million (ppm) in 144Sm with respect to other meteorites and terrestrial standards, leading to a decrease in their 142Nd/144Nd ratios by ~11 ppm. The data require that samarium and neodymium isotopes produced by the p process associated with photodisintegration reactions in supernovae were heterogeneously distributed in the solar nebula. Other samarium and neodymium isotopes produced by rapid neutron capture (r process) in supernovae and by slow neutron capture (s process) in red giants were homogeneously distributed. The supernovae sources supplying the p- and r-process nuclides to the solar nebula were thus disconnected or only weakly connected.

Radiogenic Isotope Geochemistry Laboratory, Department of Earth Sciences, Dartmouth College, 6105 Sherman Fairchild Hall, Hanover, NH 03755, USA.

* To whom correspondence should be addressed. E-mail: mukul.sharma{at}dartmouth.edu

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