Examples of line-profile shape and variability for the sample of stars quoted in Table 3 and discussed in Sect. 4. The three profiles shown in each panel correspond to different epochs in which the line-asymmetry analysis has resulted in the maximum, minimum, and mean values of RSk, respectively, as derived from the whole time series (see gray filled circles in Fig. 11). Note: HD 199579 and HD 111123 are two single line spectroscopic binaries; in both cases the line-profiles have been shifted in radial velocity to account for the orbital motion of the stars.