A Long-Period Spectroscopic Binary in the O-Star Multiple System HD 193322
Bolton, C. T.; Fullerton, A. W.; Gies, D. R.; Bagnuolo, W. G., Jr.; Penny, L. R.; Hartkopf, W. I.; McKibben, W. P.; Hahula, M. E.; Roberts, L. C., Jr.; Mason, B. D.; Thaller, M. L.
United States, Canada
Abstract
We present radial velocity measurements and a single-lined spectroscopic orbit for the bright O-type star, HD 193322A, which we show to be a 311 day binary system that has a distant third companion (detected by speckle interferometry) in a 31 yr orbit. We suggest that the speckle companion appears in the spectrum as a broad-lined component of early B type. We also present a spectrum of the visual companion, HD 193322B, which appears to be an unresolved, double-lined spectroscopic binary. Thus, HD 193322, the central object in the open cluster Collinder 419, is a multiple system that contains at least five stars (possibly seven if the C and D components are physical). Such systems may play a key role in the dynamical ejection of runaway stars from young clusters.