Pulsating Stars

David S. King, John P. Cox
1968 Publications of the Astronomical Society of the Pacific  
The current status of our understanding of the causes and nature of stellar pulsation, as applied to classical cepheids, RR Lyrae variables, and W Virginis variables, is reviewed. The historical development of these ideas is briefly surveyed, with emphasis on the search for the excitation mechanism ( s ). Tests of the idea that the instability is due to the ionization of one or more of the elements H, He, and He + in the stellar envelope, by means of both the linear and the more recent
more » ... ore recent nonlinear calculations, are described and summarized. Some comparisons of theory and observation are made, particularly with respect to the period-luminosity relation, location of variables in the Hertzsprung-Russell diagram, fundamental versus first overtone mode, and phase relations between light and velocity curves. A number of special problems are discussed, including causes of the limitation of the pulsation amplitude to the observed values, relations between the light and velocity variations, and the interaction between pulsations and convection. A new physical interpretation, due to J. Castor, of the well-known "phase lag discrepancy" between the luminosity and radius variations is described. A number of previously unpublished results are presented, particularly with respect to recent nonlinear stellar pulsation calculations.
doi:10.1086/128650 fatcat:yzdzjjnpz5dwtm7mxoidylii6q