¹ Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, UK
² Bartol Research Institute, University of Delaware, Newark, Delaware 19716, USA

We argue that, in general, observational studies of Be-star rotation have paid insufficient attention to the effects of equatorial gravity darkening. We present new line-profile calculations that emphasize the insensitivity of line width to rotation for fast rotators. Coupled with a critical review of observational procedures, these calculations suggest that the observational parameter v sin i may systematically underestimate the true projected equatorial rotation velocity, v_e sin i, by some tens of per cent for rapid rotators. A crucial implication of this work is that Be stars may be rotating much closer to their critical velocities than is generally supposed, bringing a range of new processes into contention for the elusive physical mechanism responsible for the circumstellar disk thought to be central to the Be phenomenon.

Accepted by MNRAS
Preprints from rhdt@bartol.udel.edu
or on the web at http://arxiv.org/abs/astro-ph/0312113