Kinematics of pre-main sequence stars from the Gaia DR2 catalog
  The kinematic properties of young stars that have not yet reached the stage
of the main sequence are studied. The selection of these stars was recently
carried out by Marton et al. (2019) and Vioque et al. (2020) according to the
Gaia DR2 catalog using a number of photometric infrared surveys. We have
determined the rotation parameters of the Galaxy and the parameters of the
ellipsoids of the residual velocities. The linear velocity of the circular
rotation of a solar region around the center of the Galaxy, found using 4431
stars, is equal to V_0=229.1+-4.4 km/s. The following ellipsoid parameters of
their residual velocities are found from low-mass stars (of type T Tau):
$\sigma_{1,2,3}=(9.45,6.99,6.61)\pm(0.94,0.43,0.32)$ km/s. For stars of
intermediate masses (Herbig Ae/Be stars), their values turned out to be
somewhat larger $\sigma_{1,2,3}=(13.67,9.25,7.26)\pm(2.40,2.44,0.88)$ km/s.
Distant stars from both Catalogs trace the local spiral arm well. For 1212
stars, a new estimate of the pitch angle of the Local spiral arm is equal to
i=-8.9+-0.1 deg.
