A COLLISIONLESS SCENARIO FOR URANUS TILTING
A COLLISIONLESS SCENARIO FOR URANUS TILTING
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DOI：
10.1088/2041-8205/712/1/l44
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发表时间：
2009-12
期刊：
影响因子：
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通讯作者：
G. Boué;J. Laskar
中科院分区：
文献类型：
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作者：
G. Boué;J. Laskar
天王星自转轴的大倾角(天王星的倾斜度)的起源是关于太阳系的一个重大悬而未决的问题。据信，巨型行星的形成倾角几乎为零，而且已经表明，天王星目前的自转行为基本上是稳定的。为了解决这个问题，人们做了几次尝试。在这里，我们报告的数值模拟表明，如果天王星有额外的卫星和暂时的大倾角，天王星的轴可以在行星迁移过程中倾斜，而不需要巨大的撞击。这可能发生在尼斯模型中描述的巨行星不稳定阶段。在我们的场景中，卫星在倾斜后被迁移结束时的近距离接触弹出。该模型既能解释天王星的大倾角，又能给行星轨道演化带来新的约束。
The origin of the high inclination of Uranus’ spin-axis (Uranus’ obliquity) is one of the great unanswered questions about the solar system. Giant planets are believed to form with nearly zero obliquity, and it has been shown that the present behavior of Uranus’ spin is essentially stable. Several attempts were made in order to solve this problem. Here we report numerical simulations showing that Uranus’ axis can be tilted during the planetary migration, without the need of a giant impact, provided that the planet had an additional satellite and a temporary large inclination. This might have happened during the giant planet instability phase described in the Nice model. In our scenario, the satellite is ejected after the tilt by a close encounter at the end of the migration. This model can both explain Uranus’ large obliquity and bring new constraints on the planet orbital evolution.