Abstract
The circumstellar disks ejected by many rapidly rotating B stars (so-called Be stars) offer the rare opportunity to study the structure and dynamics of gaseous disks at high spectral as well as angular resolution. Recent works, largely based on optical long baseline interferometry, showed that Achernar (α Eridani, HD10144), the brightest (V=0.46 mag) and nearest (distance of 42.75 pc) Be star is a key target to a deeper understanding of the physics of Be stars, because it displays most of features that characterizes the Be phenomenon: (i) Strong rotational rate; (ii) Residual disk; (iii) Episodic mass ejections; (iv) Quasi-cyclic disk formation/dissipation; (v) Polar wind; and (vi) Binarity.
