A KINEMATICAL STUDY OF RAPIDLY OSCILLATING AP STARS

A kinematical study of rapidly oscillating Ap (roAp) stars and of a sa mple of apparently similar Ap stars that show no pulsation is performe d, with a view to investigating possible differences between the two g roups. The mean absolute magnitudes of the stars of both samples, deri ved through the mean parallax method, are at most marginally different . From the consideration of the velocity ellipsoid parameters and of t he mean orbital elements characterizing their motion in the Galaxy, th e roAp stars appear significantly older than their non-pulsating count erparts.