小惑星の超壊滅的な破壊

Mikael Granvik^1,2, Alessandro Morbidelli³, Robert Jedicke⁴

¹Department of Physics, PO Box 64, 00014 University of Helsinki, Finland.

Nature

|February 19, 2016

まとめ

近地小惑星は,熱分解により,しばしば太陽の近くから消えていきます. 低アルベドの小惑星は分解する傾向があり,太陽の近くで観測される暗い物体の希少性を説明する.

科学分野:

天文学
惑星科学
天体物理学

背景:

地球に近い物体 (NEO) は小惑星帯から発生します.
非重力的な熱力と共鳴の脱出路が NEO を惑星を交差する軌道に駆り立てます
モデルでは太陽の近くで NEO が多く見られることが予測されていますが観測されたものはほとんどありません

研究の目的:

NEO検出を観測選択効果を考慮するモデルと量的に比較する.
特にアルベド分布に関して,太陽近くの予測されたおよび観測されたNEO集団の間の不一致を調査する.
太陽系内部の低アルベド小惑星の不足の原因を特定するためです

主な方法:

実際の小惑星検出データと近地物体モデルの比較.
小惑星検出における観測選択効果の分析.
周日距離とアルベドに基づく小惑星崩壊メカニズムの定量評価.

主要な成果:

数十の太陽半径の近日距離で超大破滅的な破裂を経験します
破裂の距離は小惑星の大きさと逆に関係している.小さい小惑星は太陽から遠く離れている.
低アルベドの小惑星は,高アルベドの小惑星よりも太陽から遠く離れる可能性が高く,太陽の近くに観測された赤字を説明します.

結論:

太陽に近い低アルベドNEOの観測不足は,それらのより頻繁で遠い熱分解に起因する.
低アルベドの小惑星は熱分解に容易になり,ほぼ完全な分解につながります.
この低アルベド小惑星の熱的脆弱性は,太陽系内部の高アルベドのNEOsの明らかな過剰を説明します.

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