A sextet of clusters in the Vela OB2 region revealed by Gaia

TL;DR

This study uses Gaia DR2 data combined with ground-based photometry and radial velocity measurements to identify six stellar clusters in the Vela OB2 region, revealing new clusters and insights into their formation history.

Contribution

The paper introduces a clustering analysis method that combines positions, proper motions, and parallax to discover new stellar clusters using Gaia data.

Findings

Discovered 6 clusters or associations, 4 of which are new.

Identified that 4 clusters formed coevally 10 Myr ago.

Found that NGC 2547 and a new cluster formed 30 Myr ago.

Abstract

Using Gaia DR2 data, combined with OmegaCAM ground-based optical photometry from the AD-HOC survey, and detailed Radial Velocity measurements from ESO-Gaia, we analyse in detail a 10x5 deg region around the Wolf-Rayet star $\gamma^2$ Vel, including the previously known clusters Gamma Vel and NGC2547. Using clustering analysis that considers positions, proper motions and parallax, we discover 6 clusters or associations -- 4 of which appear new. Analysis of the colour-magnitude diagram for these clusters show that 4 of them formed coevally from the same molecular clouds 10 Myr ago, while NGC 2547 formed together with a newly discovered cluster 30 Myr ago. This study shows the incredible wealth of data provided by Gaia for the study of young stellar clusters.