Kinematics of pre-main sequence stars from the Gaia DR2 catalog

TL;DR

This study analyzes the kinematic properties of pre-main sequence stars using Gaia DR2 data, determining Galactic rotation parameters, residual velocity ellipsoids, and the local spiral arm's pitch angle.

Contribution

It provides new measurements of Galactic rotation, residual velocity ellipsoids for different star types, and refines the local spiral arm's pitch angle based on young star kinematics.

Findings

Galactic rotation velocity V_0=229.1 km/s

Residual velocity ellipsoid parameters for low- and intermediate-mass stars

New estimate of the local spiral arm's pitch angle i=-8.9 degrees

Abstract

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.