Kinematics of Open Star Clusters Based on the Data of the New Version of the “Homogeneous Catalog of Open Cluster Parameters”

Abstract

We investigate some aspects of Galactic disc kinematics based on the data on open clusters from the current version of “The Homogeneous Catalog of the Main Parameters of Open Star Clusters” and from Gaia DR2. Based on the radial velocity and proper motion data for the clusters we determine the angular velocity of the Sun in the Galaxy as Ω₀ = 25.6 ± 1.2 km s^-1 kpc^-1. A new approximation of the Galactic rotation curve by a polynomial in inverse powers of galactocentric distances is constructed. We consider the influence of spiral density waves on the smoothed velocity field of the Galactic disc. The radial f_R = 4.6 ± 0.7 km s^-1 and tangential f_ϑ = 1.1 ± 0.4 km s^-1 amplitudes of the velocity field distortion are estimated from the radial dependences of the residual spatial velocity components of the clusters.