Abstract
We have analyzed the kinematics of open star clusters (OSCs) with their characteristics from the new catalog of Hunt and Reffert. From 4003 OSCs younger than 200 Myr we have found the following parameters of the angular velocity of Galactic rotation: \(\Omega_{0}=28.99\pm 0.11\) km s \({}^{-1}\) kpc \({}^{-1}\) , \(\Omega^{\prime}_{0}={-}3.909\pm 0.026\) km s \({}^{-1}\) kpc \({}^{-2}\) , and \(\Omega^{\prime\prime}_{0}=0.662\pm 0.018\) km s \({}^{-1}\) kpc \({}^{-3}\) , where \(V_{0}=234.8\pm 3.0\) km s \({}^{-1}\) for \(R_{0}=8.1\pm 0.1\) kpc. We have established that a periodicity in the radial OSC velocities manifests itself for clusters younger than 600 Myr, while a wave in the residual tangential velocities manifests itself only for the youngest clusters younger than 40 Myr. Based on a spectral Fourier analysis of the radial velocities of three OSC samples with mean ages of 18, 72, and 143 Myr, we have obtained the following values of the wavelength \(\lambda\) and the velocity perturbation amplitude \(f_{R}\) : \(\lambda=2.0\) kpc and \(f_{R}=4.3\) km s \({}^{-1}\) , \(\lambda=2.2\) kpc and \(f_{R}=8.2\) km s \({}^{-1}\) , and \(\lambda=2.1\) kpc and \(f_{R}=9.6\) km s \({}^{-1}\) , respectively. We have established a systematic change in the positions of the wave maxima and minima in the radial OSC velocities as a function of the sample age. From our analysis of these shifts we have found the absolute value of the difference \(|\Delta\Omega|\) of the spiral pattern speed \(\Omega_{p}\) and the angular velocity of Galactic rotation, \(|\Delta\Omega|=2.0\pm 0.5_{\textrm{stat}}\pm 2.3_{\textrm{syst}}\) km s \({}^{-1}\) kpc \({}^{-1}\) . On this basis, we have estimated two possible corotation radii, \(8.6\pm 0.2\) and \(7.6\pm 0.2\) kpc, suggesting that the Sun is very close to corotation.
