Standard models of planet formation explain how planets form in axisymmetric, unperturbed disks in single star systems. However, it is possible that giant planets could have already formed when other planetary embryos start to grow. We investigate the dynamics of planetesimals under the perturbation of a giant planet in a gaseous disk. Our aim is to understand the effect of the planet’s perturbation on the formation of giant planet cores outside the orbit of the planet. We calculate the orbital evolution of planetesimals ranging from 10¹³ to 10²⁰ g, with a Jupiter-mass planet located at 5.2 au. We find orbital alignment of planetesimals distributed at ≃9–15 au, except for the mean motion resonance (MMR) locations. The degree of alignment increases with increasing distance from the planet and decreasing planetesimal mass. Aligned orbits lead to low encounter velocity and thus faster growth. The typical velocity dispersion for identical-mass planetesimals is except for the MMR locations. The relative velocity decreases with increasing distance from the planet and decreasing mass ratio of planetesimals. When the eccentricity vectors of planetesimals reach equilibrium under the gas drag and secular perturbation, the relative velocity becomes lower when the masses of two planetesimals are both at the larger end of the mass spectrum. Our results show that with a giant planet embedded in the disk, the growth of another planetary core outside the planet’s orbit might be accelerated in certain locations.

行星形成的标准模型解释了行星如何在单星系统中的轴对称、未受扰动的盘中形成。然而，当其他行星胚胎开始生长时，巨行星可能已经形成。我们研究了在气态盘中巨行星扰动下微星的动力学。我们的目标是了解行星的扰动对行星轨道外巨行星核形成的影响。我们计算了从 10 ¹³到 10 ²⁰的小行星的轨道演化g，木星质量的行星位于 5.2 au。我们发现星子的轨道排列分布在≃9-15 au，除了平均运动共振（MMR）位置。对齐的程度随着与行星距离的增加和行星质量的减少而增加。对齐的轨道导致低相遇速度，从而导致更快的增长。相同质量小行星的典型速度色散为除了 MMR 位置。相对速度随着距行星距离的增加和微星质量比的减小而减小。在气体阻力和长期摄动作用下，当星子的偏心率矢量达到平衡时，当两个星子的质量都在质谱的较大端时，相对速度变低。我们的结果表明，当一颗巨大的行星嵌入盘中时，行星轨道外另一个行星核心的生长可能会在某些位置加速。