The Velocity-Curve of XY Leonis.

Abstract

Spectrograms of XY Leonis taken in January, 1959, show double absorption lines corresponding to two K0-type stars in a W Ursae Majoris type system; = -20 km/sec, K1 = 135 km/sec, K2 = 170 km/sec. The spectrum shows double narrow emission lines of Ca ii belonging to the approaching star of larger mass. There are no emission lines belonging to the receding star of smaller mass. At the opposite elongation the receding star of larger mass and the approaching star of smaller mass each has a single Ca ii emission line. The widths of the individual emission components are always much smaller than the widths of the corresponding absorption components.