New pulsating pre-main sequence (PMS) stars have been discovered in the young open clusters IC 4996 and NGC 6383 using CCD time series photometry in Johnson B and V filters. As the cluster ages are both smaller than 10 million years, all members later than spectral type A0 are still contracting towards the ZAMS, hence providing ideal candidates for searches of pulsation. A dozen stars in NGC 6383 and 35 stars in IC 4996 lie within the boundaries of the classical instability region in the Hertzsprung-Russell (HR) diagram, but pulsation was detected for only two of them in each cluster.

For the well-studied cluster NGC 2264, the two already known PMS pulsating members, V 588 Mon and V 589 Mon, have been analysed using new data from a multi-site campaign. All data collected since their discovery in 1972 build the basis for the first measurements of period changes in PMS pulsators.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html