Photometric variability of AP and He-weak stars in clusters and associations. II.

Periods and lightcurves based on data gathered in the Geneva photometric system are given for 19 CP2 and CP4 stars belonging to 11 clusters and associations. In addition, the lightcurve and approximate period is given for HD 22114, a field Ap star recently discovered by means of Geneva photometry. The strange behavior of the star HD 37151 is confirmed, althouugh it shows only one stable period. A cosinusoid with its first harmonic is fitted to each lightcurve and the covariance matrix of the errors on the fitted parameters is given, as well as the uncertainty on the period. This work confirms that hot magnetic stars undergo no braking of their axial rotation during their main sequence lifetime and that conservation of angular momentum suffices to explain the slight increase of period with age.