Non-radial pulsation
Surface shape of non-radially pulsating stars is periodically distorted in a complex way. The main effect on spectral line profiles comes from different Doppler shift due to variation of local velocity with respect to distant observer. The corresponding perturbations in the spectral lines can propagate both from blue to red or from red to blue. This variability strongly depends on angular degree
l and azimuthal order
m numbers of the dominant pulsation mode excited in the star.
