论文标题
白色矮人周围的行星碎屑盘的生命
The lifetimes of planetary debris discs around white dwarfs
论文作者
论文摘要
行星光盘的寿命绕着白色矮人绕着该系统的进化模型表示至关重要的输入参数。在这里，我们将纯粹的分析形式主义应用于估算这些圆盘碎片相的寿命，然后才能将其倒入灰尘或可能从白矮人中升华。我们计算三种不同类型的白色矮盘的最大寿命，由（i）在2-100 au沿巨大的分支阶段辐射的外囊式辐射分解，（ii）这些次要行星在$ \ sim 1.5-4.5r _ {\ odot _ {\ odot} $和（iii ii and（iii ii and（iii ii and））中，这些次要行星的无辐射旋转破坏在$ 1.3R _ {\ odot} $。我们将这些最大寿命作为圆盘质量和程度，构成的行星特性以及偏心和倾斜度的代表性轨道激发的函数。我们发现，有足够长的时间的年轻圆盘量高达$ 10^{24}。这些次要行星或主要行星的自旋或潮汐破坏形成的碎屑盘可以在稳定状态下生存，以分别为1 MYR或0.01 MYR，尽管大多数潮汐盘会在约1年内留下稳态。我们的结果表明，无防尘的行星转运检测是合理的，并且将提供特别强大的进化约束。我们的形式主义很容易适应单个系统和未来的发现。
The lifetime of a planetary disc which orbits a white dwarf represents a crucial input parameter into evolutionary models of that system. Here we apply a purely analytical formalism to estimate lifetimes of the debris phase of these discs, before they are ground down into dust or are subject to sublimation from the white dwarf. We compute maximum lifetimes for three different types of white dwarf discs, formed from (i) radiative YORP breakup of exo-asteroids along the giant branch phases at 2-100 au, (ii) radiation-less spin-up disruption of these minor planets at $\sim 1.5-4.5R_{\odot}$, and (iii) tidal disruption of minor or major planets within about $1.3R_{\odot}$. We display these maximum lifetimes as a function of disc mass and extent, constituent planetesimal properties, and representative orbital excitations of eccentricity and inclination. We find that YORP discs with masses up to $10^{24}$ kg live long enough to provide a reservoir of surviving cm-sized pebbles and m- to km-sized boulders that can be perturbed intact to white dwarfs with cooling ages of up to 10 Gyr. Debris discs formed from the spin or tidal disruption of these minor planets or major planets can survive in a steady state for up to respectively 1 Myr or 0.01 Myr, although most tidal discs would leave a steady state within about 1 yr. Our results illustrate that dust-less planetesimal transit detections are plausible, and would provide particularly robust evolutionary constraints. Our formalism can easily be adapted to individual systems and future discoveries.
