Abstract

A number of spectrograms of each of these eclipsing binaries have been obtained at the McDonald Observatory, with a dispersion of 76 A/mm at H-y. The spectral lines of All Vir break up into components at quadrature. The difference in intensity of the components is greatest at phase 0.75 P and is least at phase 0.25 P. On the assumption of a circular orbit, it is found from the velocity-curve that ~y = +10 km/sec; Kb = 105 km/sec; K1 = 250 km/sec. In many respects the spectroscopic behavior of this binary bears a close resemblance to that of YY En, another eclipsing variable of the W Ursae Majoris type. The mass functions are mb sin3 i = 1.33 and m1 sjn3 i = 0.56. It appears to be fairly general that the mass ratio as given by Kb/Kf differs from unity by an amount greater than can be reconciled with the mass- luminosity relation. From the light-curve given by Lause, the photometric elements have been derived on the assumption of uniform disks and similar ellipsoidal shapes for the components of the binary. It is found that P = 0.407 day, Lb = 0.65, rb = 0.44, k = 1.67, i = 82~9, y = 0.67. The spectral lines of TZ Boo do not be- come double at quadrature. Although the range of variation is about 60 km/sec, there does not seem to be any correlation between the radial velocity ahd phase as calculated from the period of light-varia- tion. The mean velocity is -58 km/sec