Abstract

An examination of the orbital motion in 6i Cygni,from 232 multiple-exposure photographic plates taken with the long-focus refractors at Potsdam, Lick, Sproul, Yerkes, Lowell and Dearborn Observatories, confirms the perturbation previously announced (Strand 1943), which was based on part of the present material, 47 plates. While the early plates in the series cover the years 1914-18, the majority of the plates were taken between 1937 and 1955, during which time plates were obtained at each opposition except for the years 1938 and 1944. The new investigation leads to a circular orbit with a = "0102 + "0012 (m.e.) and a period of 4.8 years against the previously found period of 4.9 years. With 720 years for the period of the large orbit, a = 24'.'616, and the parallax "294, the total mass of the system is I.13O with MA = MB = .54 and Mc = .oo8. The mass of Component C has been derived under the assumption that it contributes no light to the observed motion. Strand, K. Aa. 1943, Proc. Amer. Phil. Soc. 86, 364. Dearborn Observatory, Evanston, Ill.