This award will support an an observational program to study the Be class of stars and their surrounding disks. Observationally, Be stars are intermediate-mass stars with temperatures about 9000 K that show emission lines in their spectra from circumstellar material. While Be stars have been studied for a long time, recent data on high-energy particle emission has spurred a new interest in these objects. Dr. McSwain and her group have discovered a large population of very active Be stars in a young open clusters, and now wish to perform detailed studies of these stars. They will perform a photometric study of nonradial pulsations of Be stars, produce accurate models of nonradial pulsations on the distorted surfaces of rapidly rotating stars, model the flow of material into a circumstellar disk, and compare the predicted disk masses to observations of observed disk growth episodes.
The research is expected to shed light on the effects of rapid rotation upon stellar structure and evolution, surface activity and mass loss via stellar pulsations, and upon very high energy particle acceleration produced by the interactions of the disk with a compact companion.