大量の隕石が大気中に分解した時の隕石粉です
Andrew R Klekociuk1, Peter G Brown, Dee W Pack
1Space and Atmospheric Sciences, Australian Antarctic Division, Kingston, Tasmania 7050, Australia. andrew.klekociuk@aad.gov.au
Nature
|August 27, 2005
まとめ
地球の大気圏に衝突する大型隕石は,微米の大きさの大きな塵を発生させ,それが主にナノメートルの粒子を形成するという理論に異議を唱える. この発見は,大気中の隕石塵の主要な源であることを示唆している.
科学分野:
- コスミック・ダスト (宇宙の塵)
- 大気科学 大気科学
- 地質化学 地質化学
背景:
- 地球の大気中の隕石の消去は,それらの質量のほとんどを消費します.
- 理論的なモデルは,消去された物質がナノメートルサイズの粒子 (隕石の煙) に再収縮することを予測しています.
- 隕石の煙の直接的な測定は欠けています.
研究 の 目的:
- 大きな隕石の消去によって生じた粒子の大きさの分布を調査する.
- 観測データを,隕石の煙の形成に関する理論的予測と比較する.
- 地球の大気中のマイクロメートルサイズの隕石塵の主要な源を決定する.
主な方法:
- 大気中のエアロゾール組成の分析,大型の隕石が崩壊した後の分析.
- 残りの大気中のエアロゾールの粒子の大きさの特徴.
- 観測された粒子の大きさを,アブレーションと凝縮の理論モデルと比較.
主要な成果:
- 残留大気中のエアロゾールへの主要な貢献は,ナノメートルの粒子ではなく,マイクロメートルの粒子でした.
- この観測は,サブマイクロメートルの粒子への効率的な変換の支配的な理論と矛盾しています.
- 解体イベントは,隕石の除去中に粒子の形成の直接的な証拠を提供しました.
結論:
- 大規模な隕石は,これまで考えられていたよりもマイクロメートルの隕石粉のより重要な源である可能性があります.
- この研究は,隕石の除去と粒子形成に関する既存のモデルに異議を唱えている.
- 大規模な隕石からマイクロメートルの粒子の形成の有無を確認するためにさらなる研究が必要である.
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