水蒸気ジェットは,エンケラドスを離れるガスの羽根の中に入ります
C J Hansen1, L W Esposito, A I F Stewart
1Jet Propulsion Laboratory/California Institute of Technology, Pasadena, California 91109, USA. candice.j.hansen@jpl.nasa.gov
Nature
|November 28, 2008
まとめ
土星から水蒸気の羽根が浮かび上がる.
科学分野:
- 惑星科学は惑星科学である.
- 天体生物学 アストロバイオロジー
- 地質物理学 地質物理学とは地質物理学です.
背景:
- 土星の衛星であるエンケラドスは,南極圏から水蒸気の羽根を放出しています.
- 潮の力は,エンケラドスの内部海洋からの裂け目と水蒸気の放出に影響を与えます.
- 羽根の組成と密度を理解することは,排気管の潮制御を研究する上で鍵となる.
研究 の 目的:
- エンケラドスの水蒸気雲の密度と特性を分析するために.
- 羽毛の特徴と潮のストレスとの関係を調査する.
- 羽根の起源と加速メカニズムに関する仮説を支持または反論するために.
主な方法:
- 2007年10月24日,エンケラドスの羽根によって恒星の隠蔽の観測.
- 背景のプルーム内の高密度のガスジェットの分析.
- 水柱密度とジェット速度の測定.
主要な成果:
- 4つの高密度のガスジェットが検出され,以前に報告された塵ジェットと一致しました.
- 観測された水柱密度は,以前の測定値の約2倍でした.
- 垂直速度と熱速度の比率 (1.5 +/- 0.2) は,液体の水源と超音速ガス加速をサポートしています.
結論:
- 観測された羽根の密度は予測を上回り,複雑な換気ダイナミクスを示しています.
- この発見は,液体の水がノズルのようなチャネルを通って噴出するという仮説を裏付けている.
- エンケラドスの羽根は,地表の海活動と潮の相互作用に関する重要な洞察を提供します.
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