Galactic Rotation Based on OB Stars from the Gaia DR2 Catalogue

摘要

We have studied a sample containing similar to 6000 OB stars with proper motions and trigonometric parallaxes from the Gaia DR2 catalogue. The following parameters of the angular velocity of Galactic rotation have been found: omega(0) = 29.70 +/- 0.11 km s(-1) kpc(-1), omega'(0) = -4.035 +/- 0.031 km s(-1) kpc(-2), and omega (0) = 0.620 +/- 0.014 km s(-1) kpc(-3). The circular rotation velocity of the solar neighborhood around the Galactic center is V-0 = 238 +/- 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(theta) = 4.4 +/- 1.4 kms(-1) and f(R) = 5.1 +/- 1.2 kms(-1), respectively; the perturbation wavelengths are lambda(theta) = 1.9 +/- 0.5 kpc and lambda(R) = 2.1 +/- 0.5 kpc for the adopted four-armed spiral pattern. The Sun's phase in the spiral density wave is chi(circle dot) = -178 degrees +/- 12 degrees.