Sweeping Secular Resonances in the Kuiper Belt Caused by Depletion of the Solar Nebula
Sweeping Secular Resonances in the Kuiper Belt Caused by Depletion of the Solar Nebula
复制标题
DOI：
10.1086/316856
复制
发表时间：
2000-12
期刊：
影响因子：
--
通讯作者：
M. Nagasawa;S. Ida
中科院分区：
文献类型：
--
作者：
M. Nagasawa;S. Ida
我们研究了原始太阳星云损耗期间广泛的长期共振引起的柯伊伯带天体（KBO）轨道偏心率和倾角的激发。由于星云引力势使近日点和升交点的经度旋转，星云损耗导致长期共振的迁移。在外（经典）柯伊伯带（42天文单位以外的区域），倾角和偏心率分别分布为0.6（弧度）和0.2，其均方根约为0.2（弧度）和0.1。这些大值不能仅用当前的行星扰动来解释。我们利用直接轨道积分和解析方法研究了柯伊伯带中的长期共振，发现长期共振可以解释外带的偏心率和倾角。如果最小质量星云模型中密度约为 0.1% 的残余星云在 107-108 年的时间尺度内耗尽，则外带天体的倾角将被激发到观测水平。对于倾斜激发，木星扰动和星云势是最重要的，而海王星扰动在残余星云耗尽期间不起重要作用，尽管海王星的质量需要超过其现有质量的五分之一才能激发足够的偏心率。如果对半长轴≳50天文单位处的柯伊伯带天体的进一步观测证实了我们的模型，它将为海王星的形成和太阳星云的耗尽提供重要线索。
We have investigated excitations of orbital eccentricities and inclinations of Kuiper belt objects (KBOs) caused by the sweeping secular resonances during the primitive solar nebula depletion. Since nebula gravitational potential rotates the longitudes of perihelia and ascending nodes, the nebula depletion leads to migration of secular resonances. In the outer (classical) Kuiper belt (the region beyond 42 AU), inclinations and eccentricities are respectively distributed up to 0.6 (radian) and 0.2, and their root mean squares are about 0.2 (radian) and 0.1. These large values are not explained by present planetary perturbations alone. We have investigated the sweeping secular resonances in the Kuiper belt with both direct orbital integration and the analytical method and have found that the sweeping secular resonances can account for the eccentricity and inclination in the outer belt. Inclinations of objects in the outer belt are excited to the observational level if the residual nebula with about 0.1% of the density in the minimum mass nebula model is depleted in a timescale of 107–108 yr. For inclination excitation, Jovian perturbations and nebula potential are the most important, and Neptunian perturbations do not play an important role during the residual nebula depletion, although Neptune with more than one-fifth of its present mass is needed for enough eccentricity excitation. If further observation of the KBOs at semimajor axis ≳50 AU confirms our model, it would give important clues about Neptune's formation and the depletion of the solar nebula.