レゴリット混合プロセスによるヴェスタの独特の宇宙気象
C M Pieters1, E Ammannito, D T Blewett
1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA. carle_pieters@brown.edu
Nature
|November 7, 2012
まとめ
小惑星ヴェスタは,月やイトカワとは異なり,ユニークな宇宙気象を呈しています. その表面のレゴリスは,ナノフェーズ鉄を蓄積するのではなく,小規模な混合によって時間とともに均質化します.
科学分野:
- 惑星科学 惑星科学
- アストロジオロジー アストロジオロジー
- スペクトル顕微鏡検査です.
背景:
- ヴェスタ小惑星は強いピロキセンの吸収帯を示し,特定の隕石のクラスに結びついている.
- 宇宙の気象は通常,空気のない天体のスペクトル特性を弱め,ヴェスタの強い帯を謎にしています.
- ナノフェーズ鉄の蓄積は,月と小惑星イトカワのスペクトル分解を説明する.
研究 の 目的:
- 小惑星ヴェスタのユニークな宇宙気象化のプロセスを調査します.
- ヴェスタのスペクトル吸収帯が,宇宙気象の影響にもかかわらず,なぜ強いままなのかを明らかにする.
- ヴェスタの表面の進化とレゴリット特性を記述する.
主な方法:
- ヴェスタの表面の高解像度スペクトル分析.
- ヴェスタの新鮮なクレーターと古いクレーターからのスペクトルデータの比較.
- レゴリット粒子の組成と分布の分析.
主要な成果:
- ヴェスタの宇宙気象は,月やイトカワの気象と大きく異なる.
- ヴェスタのレゴリット粒子のナノフェーズ鉄の蓄積の証拠は見つかりませんでした.
- スペクトル観測データは,ベスタの上部レゴリットが,小規模な混合によって,時間とともに局所的に均質化していることを示している.
結論:
- ヴェスタの表面の進化は,独特の宇宙気象メカニズムによって駆動されています.
- 強力なピロキセンの吸収帯は,このユニークな気象処理により保存されます.
- 多様な表面成分を小規模に混ぜ合わせると,ヴェスタの均質化されたレゴリスが形成される.
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