An investigation of photoelectric radial-velocity spectrometers as used in the analysis of Cepheid variables

The authors have used synthetic stellar spectra to simulate observations of Cepheid variables with photoelectric radial-velocity spectrometers. They have found that the projection factor used to convert radial velocities to pulsation velocities depends on stellar temperature, overall stellar radial velocity, and pulsational velocity, as well as the method used to determine the radial velocity from the cross-correlation dip. The shape of the cross-correlation dip has been found to vary with the pulsation velocity and with the parameters of the stellar models.