标题： 星子环中原行星的寡头增长 显示英文标题

标题： Oligarchic growth of protoplanets in planetesimal rings

摘要： 在标准的行星形成情景中，假设星子在整个原行星盘中形成，并且在径向方向上除了雪线以外是平滑分布的。 通过这种假设研究了星子的增长，并且寡头增长模型被广泛接受。 然而，最近对气体和尘埃演化的模拟显示，星子仅在径向有限的区域形成——例如在气体压力凸起和雪线处——并且集中在环状区域。 当星子分布在环状区域时，散射的星子会从环的边缘泄漏出来，导致星子扩散。 为了研究扩展的星子环中的原行星增长，我们进行了一系列$\textit{ N}$-体模拟。 在所有模拟中，原行星的增长可以用寡头增长来很好地解释，而由于原行星对星子的散射，环的宽度会扩大。 大质量的原行星倾向于在环的中心附近形成，而在环中心远处形成的原行星质量小于中心的原行星。 缩放后的轨道间隔既不依赖于初始环的宽度，也不依赖于总质量，并且与基于寡头增长模型和扩散星子分布的估计一致。 扩展的星子环的宽度不依赖于其初始宽度，但依赖于其总质量。 原行星的最大质量强烈依赖于环的总质量，而对初始宽度的依赖较弱。 显示英文摘要

摘要： In the standard planet formation scenario, planetesimals are assumed to form throughout the protoplanetary disk and to be smoothly distributed in the radial direction except for the snowline. Planetesimal growth has been investigated using this assumption, and the oligarchic growth model is widely accepted. However, recent simulations of gas and dust evolution have shown that planetesimals form only in radially limited locations -- such as at gas pressure bumps and snowlines -- and are concentrated in ring-like regions. When planetesimals are distributed in a ring-like region, scattered ones leak from the ring edge, resulting in planetesimal diffusion. To investigate protoplanet growth in expanding planetesimal rings, we perform a series of $\textit{ N}$-body simulations. In all the simulations, protoplanet growth is well explained by oligarchic growth, while the ring width expands due to planetesimal scattering by the protoplanets. Massive protoplanets tend to form near the ring center, and protoplanets that form far from the ring center are less massive than those in the center. The scaled orbital separations depend on neither the initial ring width nor on the total mass, and they are consistent with estimates based on the oligarchic growth model and the diffused planetesimal distribution. The width of the expanded planetesimal ring does not depend on its initial width, but it does depend on its total mass. The maximum mass of protoplanets depends strongly on the total ring mass and weakly on its initial width.