Resumen
The number of Be stars with unusually hard-thermal and variable X-ray emission like that of γ-Cassiopeiae increased from one to ten in seven years. It is possible that they could be progenitors of magnetars or account for the missing number of Be/WD binaries observed, and this can be further tested through careful characterization of the parameter space in which the X-ray emission occurs. Here, we present a compendium of the optical and X-ray properties of a sample of this new class of X-ray emitters and some very recent results presented by our group. We discuss the current understanding and emphasize results that strengthen the interpretation of magnetic activities near the Be star as being the source of the X-ray emission.
