New Expansion Rate Estimate of the Scorpius-Centaurus Association Based on T Tauri Stars from the Gaia DR2 Catalog

Abstract

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 $K=39\pm 2$ 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 $12\pm 2^{\circ }$ to the galactic plane.

arXiv comment14 pages, 2 figures, 2 tables

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• Estimation of the Gould Belt scale height from T Tauri type stars in the Gaia DR2 catalogue
• How common can the origin of clusters Cha I, Cha II, epsilon Cha and eta Cha be?
• Studying the Kinematics of the Stellar Association TW Hya from Current Data
• Kinematics of Fainst Stars of the Sco-Cen Association According to Gaia Catalog