Delta-Scuti stars in open clusters

A CCD-photometry observing program in open clusters has been begun which seeks to answer the following questions about Delta Scuti stars: why is a Delta Scuti star a variable, which modes are observed, and why these modes in particular are observed. Time series of up to eight hours per night are collected for fields of 2 x 3 arcmin. Among seven clusters only two with Delta Scuti stars have been found; and in one of them there is a need to confirm the nature of the variables. It is concluded that a picture is slowly merging which links the frequency of Delta Scuti stars, Ap stars, and active late-type stars to the age of the cluster and possibly to the dynamics during the formation of the stars, which can vary from cluster to cluster