CONTRIBUTION TO THE STUDY OF COMPOSITE SP ECTRA .7. HD-16646

HD 16646 is listed by Hynek (1938) as a star suspected of having a com posite spectrum. Classifications made by Abt and by us, and Stromgren photometry by Olsen, indicate that the star is not a spectrum binary b ut a metal-deficient F dwarf. It is, however, a binary star; 67 radial velocities, obtained at various observatories, show KD 16646 to be a single-lined spectroscopic binary with the following orbital elements: P = 328.91 days; T = 2447033.3 JD; omega = 1.degrees 8; e = 0.114; K = 11.93 km/s; V-o = -5.03 km/s; a sin i = 53.60 Gm; f(m) = 0.0568 M(ci rcle dot). The secondary component, unseen in the spectrum, may be a d warf K star; the linear separation of the components is no more than a bout 1.2 AU, and their angular separation is not expected to exceed 0. 015''.