Fundamental Physics of Stellar Pulsation

Variable stars are a class of stars which are not held at hydrostatic equilibrium, but rather oscillate about some mean radius. RR Lyrae variables are of particular interest because of their relatively long period of oscillation and quasi-equilibrium nature. This feasibly would allow RR Lyrae to be candidates for use as a standard candle in calculating astronomical distances, providing a scale for our universe. The mechanism for this stellar pulsation is mostly unknown, however certain theories point to magnetic fields storing energy or convection in the radiative zone creating abnormal behavior on the surface. In 2005, a group of astrophysicists in Germany (M. Grott, S. Chernigovski, and W. Glatzel) designed a numerical simulation for non-linear stellar pulsations, taking into account mass loss as a major contributing factor in the coupling of linear and non-linear modes of oscillation. The goal of this research is to create a numerical simulation similar to this group's work, as well as expand upon it to include more parameters. This should allow us to recreate known behavior from RR Lyrae observations made by Kenneth Carrell at Angelo State. An introductory explanation of the physics of oscillation stars will be presented along with proposed work.