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彗星9P/テンペル1の原子核で,大きな塵/氷の比率が見られる
Michael Küppers1, Ivano Bertini, Sonia Fornasier
1Max-Planck Institut für Sonnensystemforschung, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany. kueppers@mps.mpg.de
Nature
|October 18, 2005
まとめ
ディープインパクトミッションは,彗星9P/テンペル1が1より大きい塵と氷の質量比を持っていることを明らかにし,彗星が"氷の汚れ球"であることを示唆しました. 衝撃分析はまた,コマ中の塵の加速を示し,噴出を引き起こした隕石の衝突によるものではありません.
科学分野:
- 惑星科学は惑星科学である.
- 彗星科学 彗星科学
- アストロケミストリー アストロケミストリー
背景:
- 彗星は,低温で未加工の性質があるため,初期の太陽系についての洞察を提供します.
- 彗星核の内部構造と組成は,遠隔とインシットー測定にもかかわらず,まだ十分に理解されていません.
- 彗星の内部を調査することは,太陽系の形成を理解するために非常に重要です.
研究 の 目的:
- 彗星9P/テンプル1の内部をインパクターを使って探査する.
- 彗星核の組成と構造を決定する.
- 衝突後のエジェクトとアクティビティを分析する.
主な方法:
- ディープインパクトミッションでは,彗星9P/テンペル1に弾丸で衝突した.
- 発生した水蒸気と塵雲の分析.
- 塵の速度と衝突後の横断面の測定.
主要な成果:
- 衝突により,水蒸気 (4.5 x 10^6 kg) と塵 (330 km2の横断面) が大量に発生した.
- 塵と氷の質量比は"より大きいと推定され",汚れた雪球"モデルに挑戦しています.
- 高い塵の速度は,彗星の昏睡の中で加速していることを示唆し,おそらく太陽系駆動の亜鉛化によるものです.
結論:
- 彗星の核は,より高い塵の含有量があるため",氷の汚らわしい球"と表現した方がよいかもしれません.
- 太陽放射線と亜鉛化が,塵粒子を原子核から遠ざける加速に重要な役割を果たしています.
- 彗星爆発は,典型的な隕石衝突によって引き起こされる可能性は低い.
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