Dust Driven Multiphase Hydrodynamics in Planetary Nebulae

像太阳一样，普通恒星最终会耗尽它们的燃料并死亡。它们留下了美丽的身体，形状是由气体和尘埃组成的巨大发光的云，被称为行星星云。这些星云令人惊叹，五颜六色，形状多样而独特，为它们赢得了像猫眼、S眼、螺旋星和哑铃这样的名字。虽然星云是从一颗圆形恒星诞生的，但恒星在生命过程中的不同影响导致了这些形状独特的星云，原因不明。这些星云也是宇宙尘埃的重要来源；正是这种尘埃造就了我们的星球和我们。尘埃在这些星云的形成和老化过程中所起的作用还不是很清楚。研究人员研究了行星状星云的形状是如何通过气体流动、光线和尘埃粒子的相互作用来解释的，这些气体、光和尘埃粒子在恒星灭亡前刚刚出现。这些行星状星云的形成历时数千年，距离数万亿英里，这使得对它们进行实验变得困难。取而代之的是，研究人员将创建行星星云的超级计算机模拟。这些模型可以在几小时内运行，而不是数千年。这些模型更好地理解了尘埃、光和气体之间的相互作用。研究人员将把他们的模型结果与对真实行星状星云的观测结果进行比较。这个项目结合了天体物理学和工程学的知识。这种跨学科的方法也将适用于利用工程学和天体物理学来培训研究生和进行K-12外展。研究人员将创建课堂活动，帮助K-12学生理解光和物质的相互作用。这项工作的主要目标是确定尘埃在行星星云中观察到的小尺度(彗星结)和大尺度(两极轴对称抛射)流体动力学特征的形成中所起的作用。研究人员假设，这些事件是由激波和辐射驱动的流体力学中的尘埃和气体的多相耦合驱动的，这些流体动力学是由扰动的、非均匀的、初始条件引起的。这一裁决反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Average stars, like the sun, eventually use up all their fuel and die. They leave behind beautiful corpses in the form large glowing clouds of gas and dust known as planetary nebulae. These nebulae are stunning and colorful with diverse and distinctive shapes, earning them names like cat?s eye, helix, and dumbbell. While a nebula is born from a round star, different effects in the life of stars result in nebulae with these distinctive shapes, for unknown reasons. These nebulae are also important sources of cosmic dust; it is this dust from which our planet and we were made. The role of dust in the shaping and aging of these nebulae is not well understood. The investigators study how the shapes of planetary nebulae can be explained by the interactions of gas flows, light, and dust particles that come from the star, just prior to its death. The shaping of these planetary nebulae occurs over thousands of years and at distances of many trillions of miles, making it difficult to experiment with them. Instead, the investigators will create super-computer simulations of planetary nebulae. These models run in hours instead of thousands of years. These models give a better understanding of the interactions of dust, light, and gas. The investigators will compare their model results to observations of real planetary nebulae. This project combines knowledge from both astrophysics and engineering. This interdisciplinary approach will also apply to training graduate students and conducting K-12 outreach, using both engineering and astrophysics. The investigators will create classroom activities that help K-12 students understand the interactions of light and matter. The primary objective of this work is to determine the role of dust in the formation of observed small-scale (cometary knots) and large-scale (bipolar axisymmetric ejecta) hydrodynamic features found in planetary nebulae. The investigators hypothesize that these events are driven by multiphase coupling of dust and gas in shock and radiation driven hydrodynamics arising from perturbed, heterogeneous, initial conditions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.