SIMBAD references

We apply the amplitude equation formalism to the study of the nonlinear behavior of the amplitudes of triplets of modes in pulsating stars. We show that, even when they remain small, rotation-induced differences in the growth-rates of the components of a triplet and in the nonlinear coupling coefficients can generate substantial asymmetries in the amplitude Fourier spectrum of a given triplet. Furthermore, depending on the star and the specific multiplet considered, the amplitudes are constant in time or exhibit long-term modulations; the latter can be periodic or irregular. When all three component modes are excited and the amplitudes are constant then nonlinear phase-lock causes symmetric frequency spacing in the Fourier spectrum of the multiplets.