Evidence of the Galactic outer ring R1R2' from young open clusters and OB-associations

TL;DR

This study provides evidence for the Galactic outer ring R1R2' structure by analyzing the distribution and kinematics of young open clusters and OB-associations, suggesting the Sun's position near the ring's segment.

Contribution

It identifies the Galactic outer ring R1R2' using young cluster distributions and refines the Sun's position angle relative to the Galactic bar.

Findings

Optimal solar position angle theta_b=35 +/- 10 degrees.

Distribution of young clusters supports the R1R2' ring structure.

Kinematic data indicates the Sun is near the R2 ring segment.

Abstract

The distribution of young open clusters in the Galactic plane within 3 kpc from the Sun suggests the existence of the outer ring R1R2' in the Galaxy. The optimum value of the solar position angle with respect to the major axis of the bar, theta_b, providing the best agreement between the distribution of open clusters and model particles is theta_b=35 +/- 10 degrees. The kinematical features obtained for young open clusters and OB-associations with negative Galactocentric radial velocity VR indicate the solar location near the descending segment of the outer ring R2.