CW Variables of the W Virginis type. For an equal period value, the W Vir variables are fainter than the Delta Cep stars by 0.7 - 2 mag. The light curves of W Vir variables for some period intervals differ from those of Delta Cep variables for corresponding periods either by amplitudes or by the presence of humps on their descending branches, sometimes turning into broad flat maxima. W Vir variables are present in globular clusters and at high galactic latitudes. These are the classical cepheids, or Delta Cep-type variables.
DCEP stars are present in open clusters.
They display a certain relation between the shapes of their light curves and their periods. They pulsate with periods of 0.1 to 1 day, or vary in brightness with an amplitude approximately 0.1 mag. in V during a time interval of about a year. RR Variables of the RR Lyrae type, which are radially pulsating giant A-F stars having amplitudes from 0.2 to 2 mag. Like Cepheids, maximum expansion velocities of surface layers for these stars practically coincide with maximum light. RV Variables of the RV Tauri type.