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Published byMeredith Ticknor Modified over 10 years ago
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BLUE STRAGGLER STARS IN SAGITTARIUS GLOBULAR CLUSTERS Nov 06, 2012
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The context: Sgr offers a different environment to study the BS phenomenon: Star clusters associated with Sgr exhibit wide variations of age, structural and dynamical properties, and metallicity.
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The data: BV photometry, Danish telescope @LaSilla
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The Color-Magnitude Diagrams: Arp 2 and Terzan 8 are Sgr genuine members, NGC 5634 and Palomar 12 are stripped clusters, now floating in the MW halo.
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Structural properties:
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Structural properties: cont. Sgr main body clusters
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BS stars selection: Contamination taken into account in a statistical way
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BS radial distribution: Not segregated Segregated Not segregated
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BS specific frequency: Sgr Main Body contamination ????
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BS cumulative distribution: Anderson-Darling test 60 % 0.4 % 44 % 75%
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Conclusions: The main idea of this study was to use BS as test- particle to probe the parent cluster dynamical status; Their distribution nicely correlates with the King parameters of the parent clusters; Special care must be taken since contamination from Sgr Main Body can complicate significantly the interpretation.
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BS in Galactic Old Open Clusters Open clusters seem to possess the largest frequency of BS (see Yazan talk) There is a trend of having more BS at decreasing total luminosity and increasing age (De Marchi et al. 2006) Membership is a challenge (see Javier talk)
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BS in Galactic Old Open Clusters Carraro, Boffin, Ahumada, Beccari, Davies, Monaco
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BS in Galactic Old Open Clusters
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FLAMES (blue setup) + UVES Multi-epoch ( typically 3 epochs) Improving membership, improving statististics, finding pathological cases In the middle between micro- and macro-economy
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