Date of this Version
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC 97:1078-1085, November 1985.
Fourier decompositions are made of the B, V, R, and I classical Cepheid observations of Moffett and Barnes. The Fourier diagrams for V agree very well with the corresponding plots of Simon and Lee. The B, R, and I diagrams resemble the plots for V, but with small, systematic shifts in the phases ϕ21 and ϕ31. The 2.5-day star, DT Cyg, is confirmed as a likely overtone pulsator by its anomalous position in the Fourier plots. Finally, we study the Fourier phase quantity ϕ41 and introduce phase-phase diagrams to look at the Hertzsprung progression. Discontinuities in these diagrams support the idea that the long-period and short-period Cepheids may reach their limit cycles in different ways.