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星間ダイヤモンドの性質と起源
D F Blake1, F Freund, K F Krishnan
1NASA Ames Research Center, Moffett Field, California 94035, USA.
Nature
|April 14, 1988
まとめ
隕石で見つかった顕微鏡のダイヤモンドは,予想と矛盾する性質を示しています. 新しいデータによると,これは非常に細粒子のダイヤモンド材料の表面原子によるものかもしれない.
科学分野:
- 宇宙化学 (コスモケミストリー)
- マテリアルサイエンス 材料科学
- ミネラロジーは,鉱物学です.
背景:
- 顕微鏡のダイヤモンドは,炭酸性コンドライト隕石で特定されています.
- この隕石のダイヤモンド (Cデルタ成分) の特定の性質は異常に見えます.
- これらの異常は,ダイヤモンドの性質と起源に関するさらなる調査を必要とします.
研究 の 目的:
- 高空間解像度技術を使用して隕石から微小なダイヤモンドを分析する.
- 隕石ダイヤモンドの観測された性質と理論的な期待を調和させる.
- 地球外環境における顕微鏡のダイヤモンドの形成メカニズムを調査する.
主な方法:
- 高空間解像度の分析技術が採用されました.
- 隕石からのCデルタダイヤモンド成分の特徴.
- 材料の特性に対する表面と界面の原子の貢献の分析.
主要な成果:
- Cデルタダイヤモンドは,非常に細粒度 (0.5~10nm) の単相材料である.
- 表面と界面の炭素原子は,合計の25%まで,スペクトルデータに"無形"な性質を寄与します.
- 観測された性質は,細粒子の性質と表面効果によって説明できる.
結論:
- "無形"のスペクトル特性は,細粒度ダイヤモンドの表面/界面原子に起因する.
- 発見は,無形炭素とグラファイトから高圧の恒星間形成の仮説を裏付けている.
- 隕石ダイヤモンドの低圧形成メカニズムは可能性として残っている.
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