Driving white dwarf metal pollution through unstable eccentric periodic orbits
Driving white dwarf metal pollution through unstable eccentric periodic orbits
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DOI：
10.1051/0004-6361/201935996
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发表时间：
2019-08
影响因子：
6.5
通讯作者：
K. Antoniadou;D. Veras
中科院分区：
文献类型：
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作者：
K. Antoniadou;D. Veras
语境。在超过 1000 颗白矮星的大气层中观察到行星碎片，并且现在观察到两颗白矮星包含绕轨道运行的小行星。系外行星和行星核心碎片通过与主要行星的散射达到接近白矮星的轨道。然而，通过持续约 1010 年的 N 体模拟来探索允许这种散射发生的架构非常耗时；这些长时间运行的模拟限制了可研究的相空间量。目标。在这里，我们使用平面和三维（空间）椭圆周期轨道，以及通过动态稳定性图的混沌指标，作为 N 体模拟的快速无标度分析替代方案，以便在很长的时间尺度上定位和预测由一颗主行星和一颗小行星组成的白矮星行星系统的不稳定性。然后，我们根据弹射事件与碰撞事件对不稳定性进行分类。方法。我们通过允许周期性轨道的偏心率和倾斜度增加来概括我们之前的工作，从而增加更多的真实感，同时也为我们的架构带来更多的自由度。我们还进行了一套计算成本高昂的 10 Gyr N 体模拟，以提供与有限相空间区域中的混沌指标的比较。结果。我们计算特定于白矮星行星系统的动态稳定性图，可用作未来研究的工具，以快速估计单行星结构的污染前景和时间尺度。我们发现这些图也与我们 N 体模拟的结果非常吻合。结论。随着对金属污染白矮星的观测呈指数级增长，特别是在盖亚时代，周期性轨道等工具可以帮助推断系统集合的动力学历史。
Context. Planetary debris is observed in the atmospheres of over 1000 white dwarfs, and two white dwarfs are now observed to contain orbiting minor planets. Exoasteroids and planetary core fragments achieve orbits close to the white dwarf through scattering with major planets. However, the architectures that allow for this scattering to take place are time-consuming to explore with N-body simulations lasting ∼1010 yr; these long-running simulations restrict the amount of phase space that can be investigated. Aims. Here we use planar and three-dimensional (spatial) elliptic periodic orbits, as well as chaotic indicators through dynamical stability maps, as quick scale-free analytic alternatives to N-body simulations in order to locate and predict instability in white dwarf planetary systems that consist of one major and one minor planet on very long timescales. We then classify the instability according to ejection versus collisional events. Methods. We generalized our previous work by allowing eccentricity and inclination of the periodic orbits to increase, thereby adding more realism but also significantly more degrees of freedom to our architectures. We also carried out a suite of computationally expensive 10 Gyr N-body simulations to provide comparisons with chaotic indicators in a limited region of phase space. Results. We compute dynamical stability maps that are specific to white dwarf planetary systems and that can be used as tools in future studies to quickly estimate pollution prospects and timescales for one-planet architectures. We find that these maps also agree well with the outcomes of our N-body simulations. Conclusions. As observations of metal-polluted white dwarfs mount exponentially, particularly in the era of Gaia, tools such as periodic orbits can help infer dynamical histories for ensembles of systems.