论文标题
通过行星9
Tilting Uranus via Secular Spin-Orbit Resonance with Planet 9
论文作者
论文摘要
天王星的98度大倾斜度令人震惊，尚未承认一个令人满意的解释。关于天王星的旋转速率及其前列卫星系统，涉及一个巨大影响器的最广泛接受的假设涉及一个巨大的撞击器。倾斜的增加是由天王星捕获到世俗的旋转轨道共振中，这可能是一种可能的替代假设，避免了许多与巨大影响相关的问题。我们建议，如果世俗的自旋轨道共振是由天王星的倾斜度激发到其当今值，如果它是由尚未发现的尚未检测到的外部太阳系统的向外迁移驱动的，通常被称为nine。我们通过对123个N体模拟的分析，对我们的假设进行了支持，该模拟的参数及其及其迁移有不同的参数。我们发现，在多种情况下，模拟的行星9驱动天王星的倾斜度超过98度，大量数量落在该值的10％之内。我们注意到我们的结果值得注意的是，在所有情况下，都要求天王星的当前自旋轴预动力率要快得多，才能达到高倾斜度。我们得出的结论是，虽然行星九（如果存在）原则上可能是天王星的倾斜度负责的，但这种结果的可行性取决于天王星的原始预动力率。
Uranus' startlingly large obliquity of 98 degrees has yet to admit a satisfactory explanation. The most widely accepted hypothesis involving a giant impactor that tipped Uranus onto its side encounters several difficulties with regards to the Uranus' spin rate and its prograde satellite system. An obliquity increase that was driven by capture of Uranus into a secular spin-orbit resonance remains a possible alternative hypothesis that avoids many of the issues associated with a giant impact. We propose that secular spin-orbit resonance could have excited Uranus' obliquity to its present day value if it was driven by the outward migration of an as-yet undetected outer Solar System body commonly known as Planet Nine. We draw support for our hypothesis from an analysis of 123 N-body simulations with varying parameters for Planet Nine and its migration. We find that in multiple instances, a simulated Planet Nine drives Uranus' obliquity past 98 degrees, with a significant number falling within 10 percent of this value. We note a significant caveat to our results in that a much faster than present-day spin-axis precession rate for Uranus is required in all cases for it to reach high obliquities. We conclude that while it was in principle possible for Planet Nine (if it exists) to have been responsible for Uranus' obliquity, the feasibility of such a result hinges on Uranus' primordial precession rate.
