隕石のモリブデンイソトープから推論された太陽前物質の様々な超新星源

Qingzhu Yin¹, Stein B Jacobsen, Katsuyuki Yamashita

¹Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 01238, USA.

Nature

|February 23, 2002

まとめ

原始的な隕石は,モリブデンの同位体成分が太陽平均と異なるため,多様な恒星の起源を明らかにします. これは,複数の超新星爆発からの物質が,初期の太陽系に寄与したことを示唆している.

科学分野:

宇宙化学 (コスモケミストリー)
核天体物理学核天体物理学とは
惑星科学は惑星科学である.

背景:

隕石の太陽前物質は,不完全な均質化と低温処理を示しており,多様な恒星の源を示しています.
炭酸性コンドライトは太陽系の平均的な構成を表し,稀な太陽前粒子が起源のヒントを提供している.

研究の目的:

大量の炭酸性コンドライトのモリブデン同位体の組成を調べるために.
この組成が,認められた平均太陽光値と一致するかどうかを判断する.
初期の太陽系物質に寄与する核合成プロセスと恒星の源を特定する.

主な方法:

大量炭酸コンドライトにおけるモリブデン (Mo) の同位体組成の分析.
隕石のデータと公認されている太陽光平均値の比較.
観測された同位体変化を説明するために,核合成プロセス (rプロセスとpプロセス) のモデリング.

主要な成果:

大量炭酸性コンドライトは,平均太陽光値とは異なるモリブデン同位体組成を示しています.
観測されたMo同位体データは,少なくとも2つの異なるr-プロセスイベントからの貢献を必要とします.
pプロセスの材料からの貢献は,rプロセスの貢献から切り離されていることが判明しました.

結論:

初期の太陽系には,複数のrプロセスのイベントと超新星から分離されたpプロセスの物質を含む,多様な恒星の源からの物質が組み込まれました.
これらの発見は,短命のイソトープと金属に乏しい星の元素分析から得られた証拠と一致し,太陽系の構成要素の複雑な起源を支持しています.

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