1995A&A...299..427M

HD 224639 was photometrically observed for 20h in 1989 and 120h in 1991 (454 and 2567 datapoints, respectively). The star shows a very complex pulsational content with 3 components with semi-amplitudes of about 15mmag and many other terms with a smaller semi-amplitude. The 1991 dataset allowed us to single out 11 components in the frequency range between 5 and 12 c/d, but many more are probably present since the residual rms of the fit is 8.6mmag, while the noise level is expected to be 3.7mmag. By subdividing the 1991 dataset into two parts and by comparing the results of the frequency analysis with those obtained from the 1989 dataset we found independent evidence in support of the reliability of four frequencies: 6.21, 8.49, 9.54 and 11.42 c/d. Since most of the 11 components are nonradial modes, their identification is hampered by the high rotational velocity (vsin i=110km/s) which very probably produces the splitting of an l mode into a multiplet (-l≤m≤+l) and, in any case, causes an appreciable shift in frequency of the central value (m=0).