论文标题
污染白矮人周围行星的高分子迁移
High-eccentricity migration of planetesimals around polluted white dwarfs
论文作者
论文摘要
已经发现了几个带有大气金属污染的白色矮人，可容纳潮汐破坏半径附近的小行星体（行星）。我们研究了这些物体的物理特性和动态起源，即它们从几个天文单位的初始距离进行了高分子迁移。我们检查了轨道迁移和圆形化的两种合理机制：紧凑型圆盘中的潮汐摩擦和拉姆压阻。对于每种机制，我们为可以重新定制各种情况的轨道演变而得出一般的分析表达式。我们确定确定行星轨道是否可以在适当的时间尺度内进行循环的物理参数，并根据观察到的系统的属性来限制这些参数。对于潮汐迁移，需要一种与熔融岩石相似的内部粘度，这可能是由潮汐加热自然产生的。为了进行圆盘迁移以操作，暗示盘的最小柱密度。推断的总圆盘质量与污染WDS积累的金属总质量的估计是一致的。
Several white dwarfs with atmospheric metal pollution have been found to host small planetary bodies (planetesimals) orbiting near the tidal disruption radius. We study the physical properties and dynamical origin of these bodies under the hypothesis that they underwent high-eccentricity migration from initial distances of several astronomical units. We examine two plausible mechanisms for orbital migration and circularization: tidal friction and ram-pressure drag in a compact disc. For each mechanism, we derive general analytic expressions for the evolution of the orbit that can be rescaled for various situations. We identify the physical parameters that determine whether a planetesimal's orbit can circularize within the appropriate time-scale and constrain these parameters based on the properties of the observed systems. For tidal migration to work, an internal viscosity similar to that of molten rock is required, and this may be naturally produced by tidal heating. For disc migration to operate, a minimal column density of the disc is implied; the inferred total disc mass is consistent with estimates of the total mass of metals accreted by polluted WDs.
