Stellar encounters as the origin of distant Solar System objects in highly eccentric orbits
Stellar encounters as the origin of distant Solar System objects in highly eccentric orbits
复制标题
恒星相遇是高偏心轨道上遥远太阳系天体的起源
作者：
S. Kenyon;B. Bromley
柯伊伯带从海王星轨道延伸到距太阳30 Au的陡峭外缘，距太阳约50 Au。在边缘之外是一个具有大轨道偏心率的稀疏物体群。海王星塑造了大多数柯伊伯带天体的动力学，但最近发现的行星2003 VB 12（塞德娜）有一个偏心轨道，近日点距离为70 Au，远远超出了海王星的引力影响。虽然经过恒星的影响可能创造了柯伊伯带的外缘，并可能将物体分散到大的偏心轨道上，但目前没有模型解释塞德娜的性质。在这里，我们表明，一个通过星星可能分散塞德娜从柯伊伯带进入其观测轨道。一颗60-80 Au的行星散布到塞德娜轨道的可能性约为50%;这一估计主要取决于飞越的几何形状。更有趣的是，塞德娜有10%的可能性是从经过的星星的外盘被捕获的。大多数捕获的天体都有非常高的轨道倾角;探测到这样的天体将证实我们太阳系中存在太阳系外行星。
The Kuiper belt extends from the orbit of Neptune at 30 au to an abrupt outer edge about 50 au from the Sun. Beyond the edge is a sparse population of objects with large orbital eccentricities. Neptune shapes the dynamics of most Kuiper belt objects, but the recently discovered planet 2003 VB12 (Sedna) has an eccentric orbit with a perihelion distance of 70 au, far beyond Neptune's gravitational influence. Although influences from passing stars could have created the Kuiper belt's outer edge and could have scattered objects into large, eccentric orbits, no model currently explains the properties of Sedna. Here we show that a passing star probably scattered Sedna from the Kuiper belt into its observed orbit. The likelihood that a planet at 60–80 au can be scattered into Sedna's orbit is about 50 per cent; this estimate depends critically on the geometry of the fly-by. Even more interesting is the ∼10 per cent chance that Sedna was captured from the outer disk of the passing star. Most captures have very high inclination orbits; detection of such objects would confirm the presence of extrasolar planets in our own Solar System.