Investigation of the kinematics of young disk populations
A.M. Mel'nik and
Received 28 January 1997 / Accepted 28 April 1997
We used both radial-velocity and proper-motion data to perform a rotation-curve solution on a combined sample of about 700 Population-I objects including young open clusters (lg A 8.1), classical Cepheids, and red supergiants. The distances of all objects are derived on a homogenized scale based on Kholopov's (1980) ZAMS, , PL relation for classical Cepheids by Berdnikov & Efremov (1985), and the absolute-magnitude calibration for red supergiants involving photometric data in Wing's eight-color narrow-band near-infrared system. We inferred = 7.3 0.3 kpc for the distance of the Sun to the Galactic center and found the following parameters of the solar apex and Galactic rotation curve: = 8.8 0.9 km s-1, = 13.5 0.9 km s-1, = 11.7 1.5 km s-1, = 27.3 2.0 km s-1 kpc-1, A = 19.5 0.5 km s-1 kpc-1, and = 1.13 0.12 km s-1 kpc-3. These values are in good agreement with the results of our analysis of the radial-velocity and proper-motion fields of classical Cepheids (Dambis et al. 1995).
Key words: Galaxy: kinematics and dynamics open clusters and associations Cepheids supergiants Galaxy: structure Galaxy: fundamental parameters
© European Southern Observatory (ESO) 1998
Online publication: December 8, 1997