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O. Manuel (U Missouri-Rolla)
Primordial He and Ne in meteorites accompany excess Xe-136 and Xe-124 and smaller isotopic anomalies of Kr and Ar, but another noble gas component there contains isotopically “normal” Ar, Kr and Xe with little or no He or Ne (Manuel & Sabu, 1977, Science 195, 208; Sabu & Manuel, 1980, Meteoritics 15, 117). These gases from outer and inner layers of a supernova (SN) first hinted that the solar system may have formed directly from heterogeneous SN debris, with cores of inner planets forming in the central Fe-rich region and the Sun forming on the collapsed SN core. Inter-linked elemental and isotopic variations in several other elements, decay products of numerous extinct nuclides, and isotopic ratios in Earth, Mars and Jupiter (Manuel et al., 1998, J. Radioanalyt. Nucl. Chem. 238, 213) all fit this scenario, but not an H-rich Sun.
The light isotopes of He, Ne, Ar, Kr and Xe in the solar wind are systematically enriched by a common mass-fractionation factor, (m-H/m-L)4.56, where m-H and m-L are the masses of the heavy and light isotopes, respectively. If selective transport of lighter particles to the solar surface produces this fractionation (Manuel and Hwaung, 1983, Meteoritics 18, 209), then the most abundant elements in the bulk Sun - Fe, Ni, O, Si, S, Mg & Ca - are the same even-Z elements that comprise 99 meteorites (Harkins, 1917, J. Am. Chem. Soc. 39, 856). Additional support for intra-solar fractionation comes from findings that heavy elements (Reames, 2000, Ap. J. 540, L111) and heavy isotopes (Rao et al., 1991, JGR 96, 19321) are enriched in solar flares relative to the solar wind. Sources of luminosity in such an Fe-rich object, the subject of our most recent study, are explored in the adjoining paper.
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The author(s) of this abstract have provided an email address for comments about the abstract: om@umr.edu or O. Manuel, 142 Schrenk Hall, University of Missouri, Rolla, MO 65401