Gravitationally Driven Instabilities in the Early & Late Stages of Stellar Evolution

Louisiana State University, Baton Rouge LA

Investigators

Abstract

Rotating stars are susceptible to a variety of global, gravitationally driven instabilities, especially during the earliest (e.g., protostellar) and latest (e.g., compact object) phases of their evolution when they are most likely to be rotating rapidly. These include, for example, a wide spectrum of nonradial pulsations. An even larger number of instabilities may be encountered by stars in binary systems through their mutual gravitational interaction, in particular, tidal and mass transferring instabilities. Any one of these instabilities may result in substantial alterations in the star's global structure and change the star's evolution. In the case of compact objects, such as neutron stars, they may give rise to measurable levels of gravitational radiation. Also, we're not likely to understand the origin of binary stars until we are able to realistically model the variety of gravitationally driven instabilities in rapidly rotating protostars and protostellar gas clouds. The Principle Investigator of this project is extending his detailed investigations of gravitationally driven instabilities in rotating stars, using fully three-dimensional, nonlinear hydrodynamical techniques to determine under what conditions certain key instabilities arise, and what the astrophysically important implications are of the nonlinear development of these instabilities. Broader Impacts. The types of high-performance computational tools that must be developed in order to further our understanding of gravitational instabilities in astrophysical systems are also used to make significant research advancements in atmospheric sciences, coastal studies, certain areas of the health sciences, and numerous subfields of engineering. This Louisiana State University researcher and his students regularly exchange ideas and computational techniques with applied mathematicians, computer scientists, and numerous colleagues who employ computational fluid dynamics tools 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 well-being. The Principle Investigator will continue to be involved in K-12 and general public outreach projects, especially those associated with the local Highland Road Park Observatory and one secondary school in Baton Rouge where substantial efforts are being made to strengthen the early training of young women in science and mathematics.