地球との出会いは,地球に近い小惑星の新鮮な表面の起源としてあります
Richard P Binzel1, Alessandro Morbidelli, Sihane Merouane
1Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. rpb@mit.edu
Nature
|January 22, 2010
まとめ
小惑星の表面は,宇宙気象の影響で急速に赤くなります. しかし,一部の小惑星は,気象による影響を受けない色を呈しており,近距離の惑星との衝突によって,潮のストレスを引き起こし,50万年以内に新鮮な表面を露出させることが説明されています.
科学分野:
- 惑星科学は惑星科学である.
- アステロイド科学 アステロイド科学
- 宇宙の気象は宇宙の気象である.
背景:
- 小惑星の色は,時間の経過とともに表面を赤くする宇宙気象による隕石のスペクトルとめったに一致しません.
- 無天候小惑星 (Q型) が観測され,特に軌道が地球と火星の近くで交差する小惑星が観測されています.
- 過去の仮説では,天候に照らされていない表面の衝突や惑星との衝突が考えられていた.
研究 の 目的:
- 天候が影響しない小惑星の表面の原因を調査するために.
- 近い惑星との遭遇がQ型小惑星の新鮮な色を説明するかどうかを判断するために.
- 小惑星の色と隕石のスペクトルの間の不一致を解決するために.
主な方法:
- 望遠鏡による小惑星の色測定の分析.
- 小惑星のスペクトルデータと実験室の隕石の反射スペクトルの比較.
- Q型小惑星の近年の接近惑星遭遇を決定するための軌道分析.
主要な成果:
- Q型小惑星は,過去50万年以内に地球から月までの距離よりも近い軌道交差を経験しました.
- これらの天候に照らされていない小惑星は,最近の近距離惑星との接触のない小惑星には含まれません.
- 証拠は,惑星との出会いを小惑星の支配的な短期的な表面再生プロセスとして支持しています.
結論:
- 近い惑星との出会いによる潮ストレスが,小惑星の表面再現の最も可能性の高い原因であり,気象に耐えない物質を暴露します.
- このプロセスは,Q型小惑星の新鮮な表面の色を説明します.
- この研究は,小惑星と隕石の色の違いに関する長年のパズルを解決した.
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