Effects of rotation on the colours and line indices of stars. VI - The reality of the blue straggler phenomenon

Abstract

The effect of rotation on the observed colors of stars has been considered as a possible cause for the blue straggler phenomenon in clusters listed by Mermilliod (1982). It appears that this phenomenon is definitely not real in the case of the late B and early A spectral type blue stragglers that are intrinsic slow rotators. Among clusters containing the early B type blue stragglers it is found that the anomalous position of the stragglers in NGC 6633, NGC 4675, and NGC 2516 cannot be accounted for by rotation effects alone