The peculiar X-ray source in NGC 5281 Original Research Article

Recent observations with Chandra and XMM-Newton have shown that the X-ray source 1WGA J1346.5–6255 is associated with the Be star HD 119682, a member of the open cluster NGC 5281, and displays all the characteristics of the new class of X-ray sources known as image-Cas analogues. We present a detailed spectroscopic study of this open cluster, finding an age of 40 Myr and a sequence of evolved stars. These results imply that HD 119682 is a blue straggler in NGC 5281, as it is much more massive than any other cluster member, and its membership is strongly suggested by proper motion analysis. This is the second image-Cas analogue found to be blue straggler in an open cluster, suggesting that evolution plays a role in the formation of these systems and that a supernova explosion has not occurred in them.