DYNAMIC PULSATION AMPLITUDES FOR A ROTATIONALLY SPLIT NONRADIAL MODE - THE L=1 CASE

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