We calibrate and then use the relation between equivalent width ( EW) and full-width-half-maximum ( FWHM) of metallic absorption lines in the spectra of RR Lyrae stars to estimate a new upper limit of Vrotsini ≤ 6 km.s −1 on their axial equatorial rotational velocities, and to derive the variations of macroturbulent velocities in their atmospheres during pulsation cycles. Finally, we present a simple way to estimate macroturbulent/rotational velocity from FWHM of the cross-correlation function.
