The effect of radial and non-radial stellar oscillations on the light, colour and velocity variations

The effect of radial and non-radial stellar oscillations on the observed light, colour and velocity variations is examined. A method of estimating the phase lag, radius and other pulsation constants is applied to classical cepheids. Amplitude and phase relations for non-radially oscillating stars are discussed with particular emphasis on the quadrupole mode. The radial pulsation and quadrupole oscillation models for β Cep stars are discussed. Some effects are predicted for multiperiodic stars and a method of determining the radius and pulsation modes is suggested. (author)