论文标题
灰尘永远不会沉降：进化的行星系统中气体和灰尘的碰撞生产
The dust never settles: collisional production of gas and dust in evolved planetary systems
论文作者
论文摘要
来自Spitzer的多上座红外光度法用于监测白色矮人的间隔盘，这与破坏的小行星是一致的，其碎屑的碎屑被积聚并由其宿主恒星化学反射。在37颗恒星中，有两个或两个以上时期的恒星中发现了广泛的红外变异性。较大的时间尺度发生了较大的通量变化，比几年的基线达到了数百万。因此，几何薄，光学厚的圆盘的规范模型不足，因为它不能引起观察到的行为。光学上的尘土最薄的可变性，碰撞驱动灰尘产生和破坏。值得注意的是，在显示Ca II发射的系统中，可以看到最高的红外变化，支持所有已知碎屑盘的行星碰撞，并且最能量的发生在患有气态碎屑的人中。该样品包括唯一的污染白色矮人，并带有环形椎间盘，其中其辐射的子三合一伴侣的昼夜循环的信号似乎被灰尘发射稀释。
Multi-epoch infrared photometry from Spitzer is used to monitor circumstellar discs at white dwarfs, which are consistent with disrupted minor planets whose debris is accreted and chemically reflected by their host stars. Widespread infrared variability is found across the population of 37 stars with two or more epochs. Larger flux changes occur on longer time-scales, reaching several tens of per cent over baselines of a few years. The canonical model of a geometrically thin, optically thick disc is thus insufficient, as it cannot give rise to the observed behaviour. Optically thin dust best accounts for the variability, where collisions drive dust production and destruction. Notably, the highest infrared variations are seen in systems that show Ca II emission, supporting planetesimal collisions for all known debris discs, with the most energetic occurring in those with detected gaseous debris. The sample includes the only polluted white dwarf with a circumbinary disc, where the signal of the day-night cycle of its irradiated substellar companion appears diluted by dust emission.
