INVESTIGATION OF THE KINEMATICS OF YOUNG DISK POPULATIONS

We used both radial-velocity and proper-motion data to perform a rotat ion-curve solution on a combined sample of about 700 Population-I obje cts including young open clusters (Ig A < 8.1), classical Cepheids, an d red supergiants. The distances of all objects are derived on a homog enized scale based on Kholopov's (1980) ZAMS, M-V(B - V)(0), PL relati on for classical Cepheids by Berdnikov & Efremov (1985), and the absol ute-magnitude calibration for red supergiants involving photometric da ta in Wing's eight-color narrow-band near-infrared system. We inferred R-0 = 7.3 +/- 0.3 kpc for the distance of the Sun to the Galactic cen ter and found the following parameters of the solar apex and Galactic rotation curve: U-0 = 8.8 +/- 0.9 km s(-1), V-0 = 13.5 +/- 0.9 km s(-1 ), W-0 = 11.7 +/- 1.5 km s(-1), omega(0) = 27.3 +/- 2.0 km s(-1) kpc(- 1), A = 19.5 +/- 0.5 km s(-1) kpc(-1), and (d(2) omega/dr(2))(0) = 1.1 3 +/- 0.12 km s(-1) kpc(-3). These values are in good agreement with t he results of our analysis of the radial-velocity and proper-motion fi elds of classical Cepheids (Dambis et al. 1995).