The Pulsation Properties of Procyon A.

Abstract

A grid of stellar evolution models for Procyon A has been calculated. These models include the best physics available to us (including the latest opacities and equation of state) and are based on the revised astrometric mass of Girard et al. Models were calculated with helium diffusion and with the combined effects of helium and heavy-element diffusion. Oscillation frequencies for l=0, 1, 2, and 3 p-modes and the characteristic period spacing for the g-modes were calculated for these models. We find that g-modes are sensitive to model parameters that effect the structure of the core, such as convective core overshoot, the heavy-element abundance, and the evolutionary state (main sequence or shell hydrogen burning) of Procyon A. The p-modes are relatively insensitive to the details of the physics used to model Procyon A and only depend on the evolutionary state of Procyon A. Hence, observations of p-mode frequencies on Procyon A will serve as a robust test of stellar evolution models.