The discovery of 13.72-min oscillations in the cool magnetic AP star HD 217522.

The discovery of oscillations with a period near 13.72 min in the cool magnetic Ap star HD 217522 is reported. Ninety-seven hours of high-speed photometric observations obtained on 18 nights spread over a time span of 74 days in 1982 are presented. The amplitude of the oscillations in HD 217522 is variable from night to night and also on a longer time-scale. A frequency analysis of the data identifies the principal frequency of oscillation to be 4.37435 + or - 0.00014 per hr. Because of the complexities of the amplitude modulation of the light curve and the very low amplitude of the light variations, the data are insufficient for a complete frequency solution. This star is the seventh member of the class of rapidly oscillating Ap stars.