Origin of Elements and Evolution of the Solar System.

O. K. Manuel 1, J. T. Lee 1, J. M. D. MacElroy 2, Bin Li 3 and W. K. Brown 4,

 
1Chemistry Department, University of Missouri, Belfield, Rolla MO 65401, USA;

2Chemical Engineering Department, University College Dublin, Dublin 4, Ireland;

3Lunar & Planetary Lab, University of Arizona,Tucson, AZ 85721;

45179 Eastshore Drive, Lake Almanor, CA 96137, USA.

"Mirror-image" isotopic anomalies [1], grain-size dependent levels of extinct 26Al [2], ranges of isotopic anomalies that also depend on grain size [3], and inter-linked chemical and isotopic heterogeneities in meteorites [4] --- these are part of a growing list of observations which indicate that the solar system formed from heterogeneous stellar debris, not by mixing 10-4 parts of exotic nucleogenetic material with 0.9999 parts normal solar system material [5,6]. These observations, and others cited below, suggest that the solar system formed from debris of a massive, spinning supernova that collapsed and exploded axially, as shown in Figure 1. According to that scenario [7], the sun formed on the SN core, iron cores of the terrest rial planets grew in an Fe-rich region around the SN core, and these were layered with a mantle of stony meteorites as condensate from an intermediate SN region fell toward the forming sun. Material consisting mostly of light elements from the outer SN layers formed the giant, low-density, Jovian planets.

Combined 244Pu and 238U dating suggests that the supernova event occurred about 5 billion years ago [8]. The earliest condensate on the 26Al-26Mg scale occurred within 1-2 million years of the supernova, as shown in Figure 2 , and trapped large isotopic a nomalies [9]. Circularly polarized light from the SN core may explain enantiomeric excesses of amino acids in carbonaceous chondrites [10]. Fowler et al. [11] note that radiation from the condensing sun may continue to produce radioactivities and light, fusile nuclei, like the excess 11B recently discovered in chondrules [12]. Nuclear ignition of material falling on the SN core probably produced chondrules by flash heating, perhaps accompanied by a g-ray burst. Intrasolar diffusion enriches H and other light nuclei at the solar surface [13,14].

Recent observations with the Hubble telescope suggest that the events shown in Figure 1 may produce a rapidly expanding bipolar nebula [15], above and below the disk of material in the star's equatorial plane. Lin et al. [16] note planets can form in this rotationally-supported disk of material, thus producing the planetary system that Wolszczan and Frail [17] observed around a collapsed SN core, pulsar PSR 1257+12. Initial elemental and isotopic heterogeneities of the parent supernova in this accretion disk would diminish with time, as would any short-lived radioactivities. This may explain the linkage between extinct radioactivities and isotopic anomalies in meteorites, as seen in Reynolds' pioneering discoveries [18] and in many more recent analyses, e.g., the X grains of SiC [9].


This paper is dedicated to the memory of Dr. Dwarka Das Sabu.

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