NGC 1817: the richest population of δ Scuti stars

We combined two sets of data to get high-precision time-series for stars in the open cluster NGC 1817. We verified most of the variable stars detected earlier and found some new ones. To the 12 δ Scuti variables detected prior to this article 4 new δ Scuti stars and one candidate have been added. In addition 3 γ Doradus candidates have been detected. The total number of variables and possible variables in NGC 1817, or in the field of view of the cluster is now up to 26. This high number of pulsating stars and especially δ Scuti variables makes this cluster an interesting asteroseismic target for future study. Using asteroseismology on δ Scuti stars will hopefully provide us with information that eventually will constrain the theoretical models of stars. This will in the end give us a much greater understanding of the evolution of stellar objects. Accepted: 2009, July 8 Individual Objects: NGC 1817