Blue Stragglers

The list of confirmed or candidates blue stragglers included in WEBDA database is based on the Catalogue of blue stragglers in open clusters published by J. Ahumada & E. Lapasset
(1995, Astron. Astrophys. Suppl. 109, 375).

The authors divided the candidate blue stragglers in three groups according to the probability that these stars are bona fide blue stragglers:

First class
They are the best blue straggler candidates. They have high membership probabilities according to proper motion and/or radial velocity studies (also the central position of a star may be sometimes taken as an additional membership indicator). Their spectra and/or location in the colour magnitude diagrams correspond with those of main sequence stars. They appear clearly separated from turn-off stars.
Second class
They are probable members according to only one membership indicator (e.g. proper motion, radial velocity or central position) and are lying on the prolongation of the main sequence.
Third class
They are located in the blue straggler area but have not any membership indicator. Stars which are probable members according to only one indicator, but are lying on the margins of the area were also included in this category.
I have included the results of this work as a valuable starting point for further studies, but I do not agree with all blue-straggler candidates proposed, especially in young clusters, as, for example, in NGC 2516. This obviously depends on a personnal interpretation of the cluster colour-magnitude diagrams and is a matter of debate.

Please, follow this link to get a list of open clusters with blue stragglers.

Last update: 6 January 1999