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Paper: The Difference Between Metal-poor and Metal-rich Binaries
Volume: 404, The Eighth Pacific Rim Conference on Stellar Astrophysics: A Tribute to Kam Ching Leung
Page: 209
Authors: Abt, H.A.
Abstract: I explored the reason why many authors differed as to whether the field metal-poor stars are deficient in spectroscopic binaries or have the same frequency as metal-rich stars. From published studies of five large samples of binaries, it is obvious that the distribution of orbital periods of metal-poor stars peaks at 875 days while that of metal-rich stars peaks at about 22 days. That means that if one uses high-dispersion spectra, one will find many binaries in both samples but if one uses low-dispersion spectra, one will fail to detect the long-period binaries and will find more binaries among the metal-rich stars. The reason for the difference in period distributions seems to be that most of the metal-poor stars have left the globular clusters quickly (within 106 yr), before most of them can form short-period binaries in three-body encounters.
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