Trans-Neptunian objects (TNOs) are remnants of a collisionally and dynamically evolved planetesimal disk in the outer solar system. This complex structure, known as the trans-Neptunian belt (or Edgeworth-Kuiper belt), can reveal important clues about disk properties, planet formation, and other evolutionary processes. In contrast to the predictions of accretion theory, TNOs exhibit surprisingly large eccentricities, e, and inclinations, i, which can be grouped into distinct dynamical classes. Several models have addressed the origin and orbital evolution of TNOs, but none have reproduced detailed observations, e.g., all dynamical classes and peculiar objects, or provided insightful predictions. Based on extensive simulations of planetesimal disks with the presence of the four giant planets and massive planetesimals, we propose that the orbital history of an outer planet with tenths of Earth's mass can explain the trans-Neptunian belt orbital structure. This massive body was likely scattered by one of the giant planets, which then stirred the primordial planetesimal disk to the levels observed at 40-50 AU and truncated it at about 48 AU before planet migration. The outer planet later acquired an inclined stable orbit (>100 AU; 20-40 deg) because of a resonant interaction with Neptune (an r:1 or r:2 resonance possibly coupled with the Kozai mechanism), guaranteeing the stability of the trans-Neptunian belt. Our model consistently reproduces the main features of each dynamical class with unprecedented detail; it also satisfies other constraints such as the current small total mass of the trans-Neptunian belt and Neptune's current orbit at 30.1 AU. We also provide observationally testable predictions.
Time-Resolved Photometry of Kuiper Belt Objects: Rotations, Shapes and Phase Functions
我们提出了一个系统的调查的基础上广泛的光学数据莫纳克亚的海王星外天体的旋转光变曲线。在我们的样本中，13个天体中有4个（相当于31%）（（33128）1998 BU 48，2000 GN 171，（20000）Varuna和1999 KR 16）显示出峰-峰范围> 0.15等的光变曲线。在通过将我们的数据与文献中可靠确定的光变曲线相结合而获得的更大样本中，22个物体中有7个（32%）显示出显著的（> 0.15星等范围）光变曲线。大约23%的采样对象的光变曲线范围> 0.4星等。奇怪的是，这些天体非常大（直径大于250公里，假设旋度为0.04），在没有自转的情况下，由于自压缩，应该接近球形。我们提出，大振幅，短周期的对象是旋转扭曲，低密度碎石桩。从统计学上看，海王星外天体的球形度低于主带小行星，这表明形成时期可能导致了更高的比角动量。除了旋转光变曲线，我们还测量了7个柯伊伯带天体在0到2度相位角范围内的相位变暗。与冥王星不同的是，测量值显示陡峭的斜坡和适度的反对浪潮，表明低散射多孔表面材料的后向散射。
