| タイトル | Enstatite Meteorites and the Original Heterogeneity of Mn-53 Distribution in the Solar Nebula |
| 本文（外部サイト） | http://hdl.handle.net/2060/19990113112 |
| 著者（英） | Lugmair, Guenter W. |
| 著者所属（英） | California Univ. |
| 発行日 | 1999-01-01 |
| 言語 | eng |
| 内容記述 | We have shown earlier that the relative abundance of radiogenic Cr-53 in bulk ordinary chondrites (approximately 0.48 epsilon) is clearly different from that in the earth-moon system (0 epsilon). The SNC parent body (Mars) is characterized by an intermediate Cr-53 excess (approximately 0.23 epsilon). We have also shown that the Mn-Cr systematics of the howardite-eucrite-diogenite parent body (HED PB, the asteroid Vesta) is consistent with the chondritic Mn/Cr ratio in the bulk HED PB and that it has a Cr-53 excess of approximately 0.5 epsilon units which is within error the same as that of chondrites. It appears that the excesses of Cr-53 in these planets are a function of their present heliocentric distance. The study of some other meteorite classes (angrites, pallasites, primitive achondrites) has shown that their Mn-CR systematics is consistent with that of the ordinary chondrites. The observed gradient in the radiogenic Cr-53 abundances can be explained by a). an early volatility controlled radial Mn/Cr fractionation in the nebula or b). an original heterogeneity of Mn-53. The first assumption, however, requires the Mn/Cr ratios of the bulk Earth and Mars to be considerably lower than the inferred model Mn/Cr ratios for these two planets. For this reason, we suggested that the observed gradient is due to an original radial Mn-53 heterogeneity in the late nebula. |
| NASA分類 | Astrophysics |
| 権利 | No Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/95699 |
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