木星の深い内部における微分回転の抑制
T Guillot1, Y Miguel1,2, B Militzer3
1Université Côte d'Azur, OCA, Lagrange CNRS, 06304 Nice, France.
Nature
|March 9, 2018
まとめ
木星の深い内部は 渦巻く大気とは違って ほぼ固く回転しています この発見はジュノ宇宙船のデータに基づいていて ガス巨人の内部構造と大気動態の洞察を明らかにしています
科学分野:
- 惑星科学
- 流体力学
- 地理学
背景:
- 木星は,異なる速度で回転する異なるゾーンとベルトで,その大気圏で異なる回転を示す.
- 木星の内部回転の理解は 構造と組成を調べる上で 極めて重要です
研究 の 目的:
- 木星の深部が 大気のように 回転しているかどうか
- 重力データを用いて,木星の大気圏の流れの深さを制限する.
主な方法:
- ジュノ宇宙船のデータからの木星の偶引力ハーモニック (J4,J6,J8,J10) の分析.
- 観測された重力ハーモニックと内部モデルからの予測の比較.
- 前もって決定された奇数重力ハーモニック (J3,J5,J7,J9) との整合.
主要な成果:
- 木星の深い内部はほぼ固体のように回転し,深さによって差分回転が著しく減少します.
- 大気圏の流れは 2千から3千5百キロの深さまで広がります
- 結果は奇数重力ハーモニックから推論された深さと一致し,電気伝導性の増加と抑制された微分回転と相関しています.
結論:
- 木星の深い内部は,大気圏で見られる強い差分回転を示さない.
- 異なる回転する大気層の深さは重力測定によって制約されます.
- この発見は,質量と電気伝導性に基づく他の巨大惑星と茶色矮星の回転を理解するための意味を持つ.
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