コンドリート隕石や火星隕石における衝撃過程のタイムスケール
P Beck1, Ph Gillet, A El Goresy
1Laboratoire de Sciences de la Terre, CNRS UMR 5570, Ecole Normale Supérieure de Lyon et Université Lyon I, 46 allée d'Italie, 69364 Lyon Cedex 7, France. pbeck@ens-lyon.fr
Nature
|June 24, 2005
まとめ
隕石の衝撃波を研究することで,衝突粒子の大きさやクレーター形成の動態が明らかになる. コンドライトの衝突は,火星の衝突よりも大きく,長く,惑星の蓄積に関する洞察を提供しました.
科学分野:
- 惑星科学は惑星科学である.
- 宇宙化学 (コスモケミストリー)
- インパクトクレーター研究
背景:
- 地球上の惑星の蓄積と隕石の配送は,広範にモデル化されています.
- 衝撃を受けた隕石は,太陽系の進化と衝突過程についての洞察を提供します.
研究 の 目的:
- コンドライトと火星の隕石のピーク衝撃圧力と衝撃期間を決定する.
- 衝撃波の大きさとクレーターの大きさを,衝撃スケーリング法を用いて母体から推測する.
主な方法:
- 隕石の切断溶融脈における微量元素分布の分析.
- 高圧鉱物データを用いて,ショックイベントの期間を推論する.
- インパクターとクレーターの大きさを推定するためにインパクトスケーリング法を適用します.
主要な成果:
- 衝撃の持続時間とインパクターサイズは,コンドライトの場合はかなり大きかった (約. 1秒,5キロメートル) と比べると,火星の隕石 (約. 10 ms, 100 m) となっている.
- 火星の隕石のインパクターとクレーターのサイズは,火星のクレーター形成の数値モデリングと一致しています.
結論:
- 火星の隕石は,火星への衝撃過程を理解するための貴重なデータを提供します.
- 最近の火星隕石は,火星の局所的な地域から発生している可能性があることを示唆しています.
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