Blue Stragglers in Galactic Globular Clusters: Playing with Specific   Quantities
  We present preliminary results obtained from the comparison of the specific frequencies of Blue Straggler Stars (BSS) detected so far in a sample of 26 Galactic globular clusters. The number of BSS seems to increase almost linearly with increasing the amount of sampled light in loose clusters, while it drops abruptly for clusters having intermediate-high central densities. In particular, a simple interpretative scenario where the BSS in loose clusters are produced from primordial binaries and those detected in high density globulars are due to star interactions leading to binary formation, merging. etc. seems compatible with these early results. The possibility that this observational evidence could be ascribed to systematic biases mostly related to the increasing difficulty to detect BSS candidates with increasing cluster concentration, is also discussed. 
F.R. Ferraro, F. Fusi Pecci, M. Bellazzini