Selected Papers

Normal Modes of Oscillation for Rotating Stars III. Variational Calculations with an Improved Set of Basis Vectors , ApJ, 301, 185-203, 1986.

Normal Modes of Oscillation for Rotating Stars IV. Nonaxisymmetric Variational Solutions for 15 Solar Mass Models , ApJ, 339, 1022-1037, 1989.

Hydrodynamical Simulations of Rotating Stars I. A Model for Sub-grid Scale Flow , ApJ, 406, 651-660, 1993.

Differential Rotation and the Convective Core Mass of Upper Main Sequence Stars , ApJ, 420, 797-803, 1994.

Normal Modes of Oscillation for Rotating Stars V. A New Numerical Method for Computing Nonradial Eigenfunctions , ApJ Suppl, 116, 57-74, 1998.

Current Work

At present, there is no method or numerical algorithm available for solving exactly the stellar pulsation equations for rotationally distorted models. That is, there is no theory of nonradial oscillations of rapidly rotating stars that can be compared with the observations of line-profile variables on the main sequence. Problems such as this which involve partial differential equations with singularities at both boundaries have resisted solution for many years. However, I have been successful in developing a numerical scheme which solves the eigenvalue problem on a 2D grid. The method is now being applied to the computation of high radial order g-modes in slowly pulsating B stars (5 solar mass). I am also interested in the low-order p-modes in rapidly rotating models that might be observable in the near future from space telescopes.

Another project is investigating nonradial oscillations of rapidly rotating models with a 2D hydrodynamics code. This approach is still very experimental and it is not clear where it will lead but I have been successful so far in extracting low-order modes from a Fourier analysis of the velocity fields. In the future, I want to study the effects of rotation on chemical mixing and convection.