New Expansion Rate Estimate of the Scorpius-Centaurus Association Based
  on T Tauri Stars from the Gaia DR2 Catalog
  The kinematic properties of the Scorpius-Centaurus association were studied
using spatial velocities of approximately 700 young T Tauri stars. Their proper
motions and trigonometric parallaxes were selected by Zari et al. from the Gaia
DR2 catalog, and radial velocities were taken from various sources. The linear
expansion coefficients new estimate of the association $K=39\pm2$ km/s/kpc is
obtained by considering the influence of the galactic spiral density wave with
an amplitude of radial disturbances $f_R=5$ km/s and solar phase in the wave
$-120^\circ$. The proper rotation of the association is shown to be small. The
residual velocity ellipsoid of these stars has semimajor axes
$\sigma_{1,2,3}=(7.72,1.87,1.74)\pm(0.56,0.37,0.22)$ km/s and is positioned at
an angle $12\pm2^\circ$ to the galactic plane.
