Parallax, Proper Motion, Acceleration, and Orbital Motion of Barnard's Star

Twenty-four early plates (1916-1919) and thirty consecutive years of photographic observations of Barnard's star covering the interval 1938-1967 confirm orbital motion with a period of 25 years and semi-axis major of 0.0275". The total number of plates is 3036, with 10,452 exposures, taken on 766 nights, with a total weight of 2056. Assuming a value of 0.15 Solar for the mass of Barnard's star, the mass of the companion is found to be 0.0016 Solar, or 1.7 times the mass of Jupiter.