| Primordial Binaries in the Globular Cluster Omega Centauri (omega Cen) (2007) | |||||||||||||
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| . In a search for spectroscopic binaries in ! Cen, the radial velocities of 310 giant stars have been monitored with multiple observations over more than ten years. The percentage of binaries with periods from those allowed by the Roche lobe limit and up to the limit set by dynamical disruption is about a factor five smaller than among G dwarfs in the solar vicinity in the same period range. Assuming a similar period distribution in ! Cen as for the nearby G dwarfs, we estimate the global binary frequency in ! Cen to be as low as 3 -- 4%. In contrast to similar stars in the field, the rich population of chemically peculiar giant stars (Ba, CH, S) in ! Cen seems to have a rather low binary frequency. The most massive of all globular clusters in our galaxy, ! Cen, is of special interest in the search for primordial binaries. With its moderate central concentration, ! Cen has probably preserved a large fraction of primordial binaries in its outer regions, since the relaxation time at the... | |||||||||||||
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