Department of Physics and Astronomy: Publications and Other Research
Date of this Version
10-1-1977
Document Type
Article
Citation
THE ASTROPHYSICAL JOURNAL, 217: 160-170, 1977 October 1
Abstract
A second-order iterative nonlinear pulsation theory is generalized to the nonadiabatic case, and employed to treat Cepheid models with linear normal-mode periods lying in the vicinity of the resonance P2/P0 = 0.5. It is shown that resonance effects occurring in the second-order terms influence the phases at which maxima appear on the theoretical velocity curves. Comparison of the iterative velocity curves with those given by hydrodynamic integration indicates good agreement in a sizable number of cases. Discrepancies which appear in a number of models are discussed. It is argued that the results of the present investigation strengthen the case for associating the bumps on Cepheid velocity curves with the resonance P2/P0 = 0.5. A brief discussion of the Cepheid "bump mass" anomaly concludes the article.
Comments
Copyright 1977 American Astronomical Society