alpha 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 an d the p-mode pulsation spectrum of the models are presented. All of the mod els were constructed using the most current stellar structure physics avail able to us, including helium and heavy-element diffusion, OPAL (Lawrence Li vermore Opacity Library) equation of state, and OPAL and Alexander opacitie s. Self-consistent models of alpha Cen A and B that satisfy the observation al constraints have an initial helium mass fraction Y-ZAMS = similar to 0.2 8. The age of the system depends critically on whether or not cc Cen A has a convective core. If it does tour best model), then alpha Cen AB is simila r 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 ;10% owing to observation al uncertainties. The Galactic enrichment parameter (Delta Y/Delta Z) for o ur best model pair is less than 1. Pulsation analyses of our best models yi eld an average large and small spacing of 101 +/- 3 mu Hz AND 4.6 +/- 0.4 m u 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, o vercoming the limitation that it is also sensitive to composition.