彗星81P/ワイルド2から,宇宙船スターダストによって捕獲された有機物質

Scott A Sandford¹, Jérôme Aléon, Conel M O'd Alexander

¹Astrophysics Branch, NASA-Ames Research Center, Moffett Field, CA 94035, USA. ssandford@mail.arc.nasa.gov

Science (New York, N.Y.)

|December 16, 2006

まとめ

彗星81P/ワイルド2のサンプルは,様々な有機化合物を明らかにし,その中には星間起源を持つものもあります. これらの地球外の有機物は,隕石や惑星間塵とは異なるユニークな組成を示しています.

科学分野:

宇宙化学 (コスモケミストリー)
天体生物学アストロバイオロジー
惑星科学は惑星科学である.

背景:

彗星のサンプルは,初期の太陽系の化学的在庫の洞察を提供します.
彗星の有機物質の組成を理解することは,天体生物学と生命の起源にとって極めて重要です.

研究の目的:

彗星81P/ワイルド2の有機成分を特徴付けるため,サンプルを採取した.
彗星の有機物質を,隕石や惑星間塵粒子のような他の地外物質と比較する.
これらの有機化合物の潜在的遺産と形成経路を調査する.

主な方法:

彗星81P/ワイルド2から帰還したサンプルの分析.
有機分子の詳細な化学および同位体分析.
隕石や惑星間塵の有機組成に関する既存のデータベースとの比較分析.

主要な成果:

彗星の有機物質は異質な分布と不均衡な組成を示しています.
有機物は酸素と窒素が豊富で,隕石やIDPと比較して芳香成分が低い.
デウテリウムと窒素-15の過剰は,いくつかの化合物の星間/星前起源を示唆しています.
芳香質が少ない有機物質の独特なクラスが特定されました.

結論:

彗星81P/ワイルド2は,識別可能な有機化合物の多様なセットを含んでいます.
これらの有機物は,同位体異常を含むユニークな特性を有しており,複雑な形成の歴史を指しています.
この発見は,地球初期にプレバイオティック分子がもたらされた経緯を理解するのに役立つ.

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