ИСТИНА

We apply various cluster-analysis techniques to the sample of 1500 young luminous stars (O-B3 I-V, B3-M5 I-II) among the Hipparcos subset of the Tycho-Gaia Astrometric Solution (TGAS) of Gaia Data Release 1 located beyond 1 kpc to identify stellar associations of based primarily on the sky positions and proper motions supplemented with spectroscopic distance estimates and radial velocities where available. We use only stars with proper-motion errors <0.3 mas/yr in both right ascension and declination. The median proper-motion error of stars in our sample is 0.06 mas/yr, which translates into a transversal velocity error of 0.55 km/s at a typical distance of 2 kpc, allowing efficient identification of star groups with common location and motion and analysis of internal motions in the groups identified. We determine the mean parameters (trigonometric parallax, distance, proper motion, radial velocity, velocity dispersion, expansion/contraction rate, kinematic age, virial mass etc.) of the associations (groups) found and use them for a Galactic rotation-curve solution.