MODELS FOR THE RAPIDLY ROTATING Be STAR ACHERNAR

摘要

We present models for the Be star Achernar (α Eri), which recent interferometric observations have shown has a photospheric shape that is significantly distorted by the effects of rotation. The models are two-dimensional, axisymmetric configurations, constructed using a new version of the self-consistent field (SCF) method for computing the structure of a rapidly, differentially rotating star. Our revised SCF technique does not suffer from the computational difficulties that affected previous implementations of the method, yielding converged stellar models regardless of mass. For models with masses like those of main sequence stars of mid- to early-B spectral type, it is possible to reproduce Achernar's inferred equatorial and polar dimensions through a combination of rotational flattening/distension and suitable inclination of the rotation axis. However, while matching Achernar's apparent shape, these models are discrepant in other respects, being (on average) cooler and more rapidly rotating than observations indicate.