Stars in the sample colored by different derived quantities against their effective temperature. Top panel: Adopted values of wind terminal velocities from the literature, whereas the bottom panel shows v_∞/v_esc, where estimates of v_esc have been corrected from centrifugal forces. The tracks and symbols are the same as in Fig.1. The average uncertainty in v_∞ is indicated as an error-bar within the legend. The black solid line corresponds to a third order regression of those stars shown with filled circles. In the bottom panel, the solid line indicates our adopted prescription for v_∞/v_esc, whereas the dashed-dotted line indicates the prescription by Lamers et al. (1995).