α Centauri AB

Detailed models of alpha Centauri A and B based on the Hipparcos, Yale, and Soderhjelm parallaxes are compared. The consequences of the uncertainty in mass, luminosity, surface temperature, and composition on the structure and the p-mode pulsation spectrum of the models are presented. All of the models were constructed using the most current stellar structure physics available to us, including helium and heavy-element diffusion, OPAL (Lawrence Livermore Opacity Library) equation of state, and OPAL and Alexander opacities. Self-consistent models of alpha Cen A and B that satisfy the observational constraints have an initial helium mass fraction Y-ZAMS = similar to 0.28. The age of the system depends critically on whether or not alpha Cen A has a convective core. If it does tour best model), then alpha Cen AB is similar to 7.6 Gyr old, and if it does not, then the binary system is similar to 6.8 Gyr old. Both ages and Y-ZAMS are accurate to +/- similar-to 10% owing to observational uncertainties. The Galactic enrichment parameter (Delta Y/Delta Z) for our best model pair is less than 1. Pulsation analyses of our best models yield an average large and small spacing of 101 +/- 3 mu Hz AND 4.6 +/- 0.4 mu Hz, respectively, for alpha Cen A, and 173 +/- 6 mu Hz and 15 +/- 1 mu Hz for alpha Cen B. Some methodologies that use p-mode frequency observations to constrain the system further are outlined. We include a simple test to determine whether or not alpha Cen A has a convective core and introduce a method to use the small frequency spacing to determine the age of system, overcoming the limitation that it is also sensitive to composition.