A view into the core of α Cen A

Abstract

We present results of modelling of α Cen A. In order to estimate the physical parameters of this star, we modelled spectroscopic, interferometric, astrometric and asteroseismic data. To that effect we chose to use a Bayesian approach to parameter estimation, which allowed us, in particular, to define our prior knowledge on the parameters. An important question we wanted to address was to assess whether or not α Cen A has a convective core. We found that the data we used give indecisive results on this issue. If the star has a convective core, and provided that overshooting is taken into account, there is a possibility for the star to be in the peculiar state in which the ppII chain is the main driver of nuclear energy generation. We also found a non-negligible probability for α Cen A to be a very early subgiant.