Gravitationally Driven Instabilities that Influence Stellar Evolution

AST-0708551 Tohline自转恒星容易受到各种全球引力驱动的不稳定性的影响，特别是在它们演化的最早和最晚阶段。双星系统中的恒星通过相互引力相互作用，可能会遇到更多的不稳定性。一旦被激活，这些不稳定性中的任何一种都可以被放大到足以驱动恒星的全球结构发生重大变化，改变其演化，或许还会发出可测量的引力辐射。事实上，探测引力辐射的能力将取决于对预期光谱的准确预测。这个项目将扩展现有的关于自转恒星中引力驱动不稳定性的工作，使用全三维、非线性流体动力学技术来确定某些关键不稳定性的条件，并研究不稳定性非线性发展的重要天体物理意义。所需的计算算法和硬件工具在大气科学、海岸研究、健康科学和工程中也有重要的研究应用。Tohline教授和他的团队经常与应用数学家、计算机科学家和许多同事交流想法和计算技术，这些人在他们的研究中使用计算流体力学来模拟飓风风暴潮、人眼中的流体流动、先进燃气轮机系统中的冷却流动、海岸侵蚀和石化搅拌罐中的反应流动。这些研究领域中的大多数都直接影响到路易斯安那州的环境和经济福祉。研究小组还将继续其K-12和一般公众宣传项目，特别是与当地天文台和一所中学有关的项目，这些学校正在作出重大努力，加强对年轻妇女的科学和数学早期培训。

AST-0708551TohlineRotating stars are susceptible to a variety of global, gravitationally driven instabilities, especially during the earliest and latest phases of their evolution. Stars in binary systems may encounter an even larger number of instabilities through their mutual gravitational interaction. Once activated, any one of these instabilities can be amplified enough to drive a substantial alteration in the star's global structure, altering its evolution and perhaps emitting measurable gravitational radiation. In fact, the ability to detect gravitational radiation will depend on the accurate prediction of the expected spectrum. This project will extend existing work on gravitationally driven instabilities in rotating stars, using fully three-dimensional, nonlinear hydrodynamical techniques to determine the conditions for certain key instabilities, and to study the astrophysically important implications of the nonlinear development of instabilities.The required computational algorithms and hardware tools also have significant research applications in atmospheric sciences, coastal studies, health sciences, and engineering. Professor Tohline and his group regularly exchange ideas and computational techniques with applied mathematicians, computer scientists, and numerous colleagues who employ computational fluid dynamics in their research to model hurricane storm surges, fluid flow in the human eye, cooling flows in advanced gas turbine systems, coastal erosion, and reacting flows in petrochemical stirring tanks. Most of these areas of research directly influence Louisiana's environmental and economic wellbeing. The research team will also continue their K-12 and general public outreach projects, especially those associated with a local observatory, and with a secondary school where substantial efforts are being made to strengthen the early training of young women in science and mathematics.