A search for Be + white dwarf binaries in 50-130 Myr old open clusters

We propose to continue our search for Be + white dwarf binaries in a sample ofnearby open clusters with ages of 50130 Myr. XMMNewton has discovered a classof GammaCaslike hard Be/Xray emitters, two of them being found in openclusters in this range of ages. These massive stars could harbour the longsought white dwarfs accreting from the Be circumstellar envelopes. So far nosuch Be + white dwarf system has been confirmed and as long as none is found themodels on which our understanding of massive Xray binary evolution are basedremain suspect. Making the census of Be + white dwarfs binaries also allows toselect between the different models explaining the Be phenomenon. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]