土星のエンケラドスのオーロラ足跡
Wayne R Pryor1, Abigail M Rymer, Donald G Mitchell
1Science Department, Central Arizona College, Coolidge, Arizona 85128, USA.
Nature
|April 23, 2011
まとめ
科学者たちは,土星の衛星エンケラドスに関連したオーロラの足跡を検出しました. これらの発見は,木星の月との相互作用に類似して,エンケラドスの変数羽の活動が土星の磁気圏に影響することを示唆しています.
科学分野:
- 惑星科学は惑星科学である.
- 宇宙物理学 宇宙物理学
- 磁気圏物理学 磁気圏物理学
背景:
- 木星と土星は磁気圏が異なっていますが,月と惑星の相互作用の類似性が提案されています.
- 土星の月であるエンケラドスの冷火山活動が,木星がイオ,ヨーロッパ,ガニメデと相互作用するように,土星と電動結合を引き起こす可能性があります.
- 以前の観測では,エンケラドスと土星の結合が,検知するには弱すぎるオーロラを生成すると予測していました.
研究 の 目的:
- エンケラドスと土星の電動結合によるオーロラからの放射の可能性を調査する.
- エンケラドスに関連したオーロラの足跡を検出し,特徴づけること.
主な方法:
- 磁場に並んだイオンと電子のビームを特定するために宇宙船のデータを分析する.
- 土星のイオノスフィアにおけるオーロラの紫外線放射の観測と検出.
- オーロラ信号とエンケラドスの位置と羽根の活動との相関.
主要な成果:
- エンケラドスから下流に発生する強力な磁場に合わせたイオンと電子のビームの検出.
- 土星のイオノスフィアのエンケラドスに関連したオーロラ足跡の発見は,スキャンのわずかな割合で観察されました.
- 磁気圏のパラメータのみに基づいた説明を超えた,オーロラ放射の大きさの顕著な変動.
結論:
- 検出された粒子束は,観測可能なオーロラを生成するのに十分なエネルギーを持っています.
- この発見は,エンケラドスに関連したオーロラが確認され,その変動性がエンケラドスの羽根活動に関連していることを示唆しています.
- この研究では,エンケラドスと土星の間の電動結合が,冷凍火山的プロセスによって引き起こされるという証拠が示されています.
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