関連する実験動画
Updated: Jun 15, 2026

11:34
Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
NASAのスターダストミッションからの彗星物質の形成年齢に関する制約
J E P Matzel1, H A Ishii, D Joswiak
1Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. matzel2@llnl.gov
まとめ
コキのような彗星のインクルージョンは,初期の太陽系固体より170万年後に形成された. これは,太陽系の内部で形成された物質が後に彗星に組み込まれることを示唆しています.
科学分野:
- 宇宙化学 (コスモケミストリー)
- 惑星科学は惑星科学である.
- イソトープ地球化学 イソトープ地球化学
背景:
- 彗星は初期の太陽系の残骸であり,その形成の洞察を提供している.
- 彗星のインクルージョン形成のタイミングを理解することは,太陽系の進化モデルにとって鍵となるものです.
研究 の 目的:
- 彗星インクルージョンの同位体組成を分析することによって,彗星インクルージョンの形成時間スケールを決定する.
- 彗星物質の形成時期を,カルシウムやアルミニウムに富んだインクルージョン (CAI) などの隕石物質と比較する.
主な方法:
- 彗星81P/ワイルド2からの耐火粒子 (コキ) で26Al-26Mg同位体の体系的測定.
- 質量スペクトロメトリを用いて同位体の豊富性を分析し,26Alの存在を制限する.
主要な成果:
- コキ粒子は放射性26Mgの証拠が見つかりませんでした.
- 粒子の形成時に26Alの豊富さの上限が確立されました: 26Al/27Al < 1 x 10(-5).
- 26Alの欠如は,CAIの形成から170万年以上後にコキが形成されたことを示しています.
結論:
- コキは,最も初期の太陽系固体 (CAI) よりもかなり後に形成されました.
- これは,太陽系内部の高温物質が処理され,太陽系外部の太陽系に輸送されたことを意味します.
- 彗星のインクルージョンは,太陽系形成の初期段階から何百万年後に彗星に組み込まれた物質を表しています.
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