Galactic Rotation Parameters Based on Stars from Activ Star-Forming Regions with Data from the Gaia DR2 Catalogue

TL;DR

This study analyzes over 25,000 young stars from Gaia DR2 to refine Galactic rotation parameters, providing updated values for angular velocity, Oort constants, and local circular velocity based on stars in star-forming regions.

Contribution

The paper presents new measurements of Galactic rotation parameters using a large sample of young stars from Gaia DR2, focusing on active star-forming regions, which improves the understanding of local Galactic dynamics.

Findings

Angular velocity of Galactic rotation: 28.40 km/s/kpc

Oort constants: A=15.73, B=-12.67 km/s/kpc

Local circular velocity: 227 km/s

Abstract

We have studied a sample of more than 25 000 young stars with proper motions and trigonometric parallaxes from the Gaia DR2 catalogue. The relative errors of their parallaxes do not exceed 10\%. The selection of stars belonging to active star-forming regions was made by Marton et al. based on data from the Gaia DR2 catalogue by invoking infrared measurements from the WISE and Planck catalogues. Low-mass T Tauri stars constitute the majority of sample stars. The following parameters of the angular velocity of Galactic rotation have been found from them: $\Omega_0 =28.40\pm0.11$ km s$^{-1}$ kpc$^{-1}$, $\Omega^{'}_0=-3.933\pm0.033$ km s$^{-1}$ kpc$^{-2}$ and $\Omega^{''}_0=0.804\pm0.040$ km s$^{-1}$ kpc$^{-3}$. The Oort constants are $A=15.73\pm0.32$ km s$^{-1}$ kpc$^{-1}$ and $B=-12.67\pm0.34$ km s$^{-1}$ kpc$^{-1}$, while the circular rotation velocity of the solar neighborhood around the Galactic center is $V_0=227\pm4$ km s$^{-1}$ for the adopted Galactocentric distance of the Sun $R_0=8.0\pm0.15$ kpc.