Velocity profiles derived for R Dor, R Cas, TX Cam and IK Tau (top to bottom) compared to the measured line-widths from lines emitted at different radii in the CSE (CO: red crosses, ortho-H₂O: blue dots, para-H₂O: green circles. The widths are measured at zero power. The radii are determined by the peak in the brightness profiles of each transition). The solid black lines give the profiles with the β given in Table 1, the dotted black lines give the profile for β = 0.6.