Kinematics of the Galaxy from a Sample of Young Open Star Clusters with Data from the Gaia DR2 Catalogue

We have selected a sample of 326 young (log t < 8) open star clusters with the proper motions and distances calculated by various authors from Gaia DR2 data. The mean values of their line-of-sight velocities have also been taken from various publications. As a result of our kinematic analysis, we have found the following parameters of the angular velocity of Galactic rotation: (0) = 29.34 +/- 0.31 km s(-1) kpc(-1), (0) = -4.012 +/- 0.074 kms(-1) kpc(-2), and (0) = 0.779 +/- 0.062 kms(-1) kpc(-3). The circular rotation velocity of the solar neighborhood around the Galactic center is V-0 = 235 +/- 5 km s(-1) for the adopted Galactocentric distance of the Sun R-0 = 8.0 +/- 0.15 kpc. The amplitudes of the tangential and radial velocity perturbations produced by the spiral density wave are f = 3.8 +/- 1.2 km s(-1) and f(R) = 4.7 +/- 1.0 km s(-1), respectively; the perturbation wavelengths are = 2.3 +/- 0.5 kpc and (r) = 2.2 +/- 0.5 kpc for the adopted four-armed spiral pattern. The Sun's phase in the spiral density wave is close to = -120 degrees +/- 10 degrees.