Comparison for HD 93521 between the observed (black) and best-fitting synthetic metal line profiles under the assumption of a spherical star (red) and a gravity darkened rotationally flattened star (blue). The light grey-shaded areas delineate the regions where the quality of the fit has been evaluated. The top panels show the synthetic profiles computed for T_eff = 31 000 K, log g = 3.7 dex, ξ = 10 km s^-1 and the abundances obtained using the ELODIE spectrum and assuming a spherical star.