隕石の均一なMo同位体組成から太陽星雲の効率的な混合
Harry Becker1, Richard J Walker
1Department of Geology, University of Maryland, College Park, Maryland 20742, USA. hbecker@geol.umd.edu
Nature
|September 12, 2003
まとめ
隕石のモリブデン同位体分析は,均一な豊富さを明らかにし,太陽系の初期に塵とガスが効率的に混合していたことを示唆しています. この均質化は,有意な同位素分断の前に発生し,初期の星雲過程をサポートしました.
科学分野:
- 宇宙化学 (コスモケミストリー)
- イソトープ地球化学 イソトープ地球化学
- 惑星科学は惑星科学である.
背景:
- 銀河の進化と恒星の核合成は,元素と同位体の豊富さの大きな変化を引き起こす.
- 太陽系の相対的な同位体均一性は,初期の太陽星雲の恒星物質の効率的な均質化を示唆しています.
- 隕石の亜センチメートルの同位体異質性は,恒星のソースメモリが保存されていることを示し,完全な均質化に挑戦しています.
研究 の 目的:
- 原始的および微分化隕石におけるモリブデン (Mo) 同位体の豊富性を調査する.
- 隕石のモイイソトープが,初期の太陽系における不完全な混合を示唆する変動を示すかどうかを判断する.
- 太陽の星雲の混合過程の範囲とタイミングを理解するために.
主な方法:
- 原始隕石と微分隕石から採取した大量サンプルの分析.
- 安定モリブデンイソトープの豊富さの高精度測定.
- 隕石のMo同位体データと地上のMo標準の比較.
主要な成果:
- 大量隕石のサンプルでは,地上のモウモウと比べてモウモウイソトープの解明可能な偏差は示されなかった.
- この均一性は,原始的な隕石と微分された隕石の両方で観察されました.
- この発見は,分析された隕石における重要な大規模なMo同位体異質性の欠如を示しています.
結論:
- ガスと塵の効率的な混合は太陽の星雲の中で発生し,少なくとも3天文単位 (au) まで広がった.
- マグネトヒドロダイナミクスの不安定性が,この初期の混合プロセスを引き起こしたのかもしれません.
- 均質化は,ガス相元素の同位体分割と,揮発性制御された化学分割に先行した.
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