暗黒の雲の中の分子形態の窒素の低分子は,暗黒の雲の中にあります
S Maret1, E A Bergin, C J Lada
1Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, Michigan 48109-1042, USA. smaret@umich.edu
Nature
|July 28, 2006
まとめ
恒星間窒素の大部分は原子であり,分子 (N2) ではない. これは,彗星の低N2と隕石や塵の窒素異常を説明し,宇宙窒素に関する以前の仮定に異議を唱える.
科学分野:
- 宇宙化学 (コスモケミストリー)
- アストロケミストリー アストロケミストリー
- 惑星科学 惑星科学
背景:
- 窒素は宇宙に豊富に存在するが,その分子形態 (N2) は星間媒質では検出が困難である.
- 彗星は,太陽の値と比較して,低いN2の豊富さと元素窒素の赤字を示しています.
- 隕石や星間塵は,窒素同位体異常が顕著である.
研究 の 目的:
- 寒い暗黒の分子雲の中で分子窒素 (N2) の豊富さを決定する.
- 星間媒質における窒素 (原子対分子) の相を調査する.
- 観測された窒素の枯渇と彗星,隕石,塵の同位体異常を説明するために.
主な方法:
- 分子窒素 (N2) の豊富さのトレーサーとして利用されたN2H+.
- 寒い暗い分子雲からのデータを分析した.
主要な成果:
- 寒い暗い雲の中のガス相における大部分の窒素が原子であり,分子 (N2) ではないことを発見した.
- 観測されたN2の濃度は,以前に想定していたよりも著しく低かった.
- 原子窒素がこれらの雲のガス相を支配することを推論した.
結論:
- 彗星の低濃度のN2は,おそらくその親黒雲の低分子窒素含有量によるものである.
- 彗星の元素窒素欠乏は,予想より低い原子酸素の豊富さに関連している可能性があります.
- 雲の中の分子窒素の希少性は,原子窒素の分断を強化することによって,隕石や星間塵における窒素同位体異常を説明する.
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