Photoelectric Studies. III. Color-Luminosity Arrays for the Coma Berenices and Ursa Major Clusters.

Magnitudes and colors of fifty-five stars in the Coma Berenices cluster and of nine nucleus stars of the Ursa Major cluster-a total of 275 observations-have been determined with a photomultiplier photome- ter attached to the Washburn 15-inch and the~Lick 12-inch refractors. With the exception of ten stars, consisting of eight known binaries, one possible nonmember of the cluster, and one shell star, those stars known from their radial velocities and proper motions to be cer- tainly members of the Coma Berenices cluster populate the sequences described in Papers I and II of this series, as follows: dwarf (16), bright-dwarf (1), blue-dwarf (5), and bright blue-dwarf (4). The nine nucleus stars of the Ursa Major cluster are distributed in the color-luminosity array as fol- lows: dwarfs (4), bright-dwarfs (1), blue-dwarfs (1), and bright blue-dwarfs (3)