1994A&A...291..820A

The generalized Fourier phase difference between the components of a multiperiodic oscillation is presented, and it is applied to the double-mode Cepheid light curve parameters. It is shown that the generalized phase difference of the combination frequency terms can give useful information on the nonlinear characteristics of the pulsation and on the possible presence of resonances between pulsation modes as in the case of the classical phase differences used for single-mode pulsators. Furthermore, it is shown the utility of the qualitative interpretation of the main characteristics of the Fourier phases in the framework of the nonlinear adiabatic treatement of double-mode pulsation on the analogy of single-mode pulsation.