Observations of Achernar with VINCI

The southern star Achernar is the brightest Be star, a class of massive and fast rotating stars. We describe here a practical application of interferometry to the observation of this star, using the VINCI/VLTI instrument in the near-infrared domain. The fast rotation of Achernar distorts its photosphere, and a relatively dense stellar wind is created by the overheated poles of this star. The presence of these two components (elliptical photosphere and extended envelope) requires the use of moderately complex models to interpret interferometric visibilities.