彗星81P/ワイルド2の元素の組成は,スターダストによって収集されたサンプルです
George J Flynn1, Pierre Bleuet, Janet Borg
1Department of Physics, State University of New York at Plattsburgh, 101 Broad Street, Plattsburgh, NY 12901, USA. george.flynn@plattsburgh.edu
まとめ
スターダストミッションのデータは,彗星81P/ワイルド2の粒子が化学的に多様であることを明らかにしています. 元素の構成は,ほとんどの元素について太陽系モデルと一致しているが,銅,亜鉛,ガリウムで濃縮されている.
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.
- 彗星科学 彗星科学
背景:
- 彗星は,初期の太陽系の残骸であり,その組成に関する洞察を提供します.
- スターダストミッションは,彗星81P/ワイルド2からサンプルを採取し,その物質を分析した.
- 彗星の元素組成を理解することは,太陽系形成のモデルを洗練するのに役立ちます.
研究 の 目的:
- 彗星81P/ワイルド2の塵粒子の元素組成を決定する.
- 彗星物質の組成を既存の太陽系組成モデル (CI隕石) と比較する.
- 彗星サンプルにおける有意な元素の枯渇や濃縮を特定する.
主な方法:
- 彗星81P/ワイルド2のエアロゲルに閉じ込められた23個の粒子と7つのクレーター残留物の元素組成の分析.
- 彗星の昏睡状態を通過した際,スターダスト宇宙船が収集した材料を利用した.
- 約180ナノグラムのスケールで化学的異質性を調査した.
主要な成果:
- 彗星の粒子には化学的異質性がある.
- 平均元素組成は,Mg,Si,Mn,Fe,Ni (35%以内) とCa,Ti (60%以内) のCI隕石組成と一致しています.
- 銅 (Cu),亜鉛 (Zn),およびガリウム (Ga) は,CI隕石と比較してワイルド2物質で濃縮されていることが判明しました.
結論:
- 81P/Wild 2からの彗星物質は,初期の太陽系物質のユニークなサンプルを提供します.
- 観測されたCu,Zn,Gaの濃縮は,CI隕石が,これらの適度な揮発性のある小元素の太陽系の大量組成を正確に表していないことを示唆しています.
- 太陽系における適度な揮発性元素の豊富さについての理解を洗練するために,さらなる分析が必要である.
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