Layered semi-convection and tides in giant planet interiors
Layered semi-convection and tides in giant planet interiors
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发表时间：
2017-10
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通讯作者：
Q. André;S. Mathis;A. Barker
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作者：
Q. André;S. Mathis;A. Barker
分层半对流可以在巨行星上运行，这可能解释了最近从朱诺观测得出的对木星中重元素分布的限制，并导致了土星的光度过剩或一些热木星的异常大半径。这是一种由密度阶梯组成的状态，其中对流层被薄的稳定分层的界面隔开。行星的潮汐消散效率很大程度上取决于其内部结构。提高我们对驱动这种消散的机制的理解是至关重要的，因为它对预测任何行星系统的长期演化都有重要的后果。在这项工作中，我们的目标是研究层状半对流区内波被其他物体(如巨行星的卫星)激发时所产生的潮汐耗散。我们发现，与均匀对流介质相比，层状半对流介质中的潮汐耗散率可以显著提高，特别是在天体物理相关的亚惯性频率范围内。因此，分层半对流可能可以解释最近在木星和土星上观察到的高潮汐耗散率。
Layered semi-convection could operate in giant planets, potentially explaining the constraints on the heavy elements distribution in Jupiter deduced recently from Juno observations, and contributing to Saturn's luminosity excess or the abnormally large radius of some hot Jupiters. This is a state consisting of density staircases, in which convective layers are separated by thin stably stratified interfaces. The efficiency of tidal dissipation in a planet depends strongly on its internal structure. It is crucial to improve our understanding of the mechanisms driving this dissipation, since it has important consequences to predict the long-term evolution of any planetary system. In this work, our goal is to study the resulting tidal dissipation when internal waves are excited by other bodies (such as the moons of giant planets) in a region of layered semi-convection. We find that the rates of tidal dissipation can be significantly enhanced in a layered semi-convective medium compared to a uniformly convective medium, especially in the astrophysically relevant sub-inertial frequency range. Thus, layered semi-convection is a possible candidate to explain high tidal dissipation rates recently observed in Jupiter and Saturn.