ICCD SPECKLE OBSERVATIONS OF BINARY STARS .10. A FURTHER SURVEY FOR DUPLICITY AMONG THE BRIGHT STARS

Speckle interferometric observations from the Canada-France-Hawaii 3.6 m and Cerro Tololo 4 m telescopes are reported for 1123 stars selected from the Yale Bright Star Catalogue in a continuing effort to detect new binaries among the bright stars. Thirty-two previously unresolved binaries have been detected, including companions to xi UMa and 15 S Mon. Measures of 107 previously resolved systems, many of which resulted from earlier speckle observations, are also presented. No evidence of duplicity within a specific (m,DELTAm,p) window of detectability was found for 984 bright stars. These observations combined with two previously published surveys represent the inspection of 2088 stars, representing 23% of the members of the Bright Star Catalogue. Many of the systems discovered earlier have shown significant orbital motions, and we present preliminary orbital elements for six binaries. Eighteen other stars previously announced as bright binaries have not been confirmed following numerous attempts to do so, and we show that their apparently spurious nature is likely due to the domination of the speckle transfer function by moderate telescope aberrations under conditions of superb seeing encountered at the CFHT in 1985. After deletion of these spurious systems, this effort has resulted in the discovery of 75 new, bright binaries. We consider some aspects of the duplicity frequencies among the diverse spectral and luminosity classes represented in this sample. We anticipate that the completion of a speckle survey of the Bright Star Catalogue would lead to the discovery of at least 200 additional binary systems with angular separations mostly below 0.''20. Many of these will have periods of the order of one decade and will be accessible to complementary radial velocity programs of enhanced precision.