Gravitationally Driven Instabilities that Influence Stellar Evolution

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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.