# Multiple kinematical populations in Vela OB2 from Gaia DR1 data

## TL;DR

This study identifies two distinct proper-motion populations in Vela OB2 using Gaia DR1 data, linking them to known clusters and providing insights into their ages and recent interactions.

## Contribution

It demonstrates the presence of two separate proper-motion populations in Vela OB2 and links them to specific clusters using Gaia DR1 data, expanding understanding of their kinematics.

## Key findings

- Two proper-motion populations dispersed over ~5 degrees.
- One population linked to NGC 2547, the other to gamma Vel.
- Both populations are approximately 10-35 Myr old.

## Abstract

Recent results using radial-velocity measurements from the Gaia-ESO Survey have led to the discovery of multiple kinematic populations across the Vela OB2 association. We present here a proper-motion study of the same region. Our aim is to test whether the radial-velocity populations have a counterpart in proper-motion space, and if so, how the two sets of kinematical data complement each other. This work is based on parallaxes and proper motions from the TGAS catalog, as part of Gaia DR1. Two distinct proper-motion populations are found dispersed across ~5 degrees (or ~30 pc at their likely distances). Their detailed correspondence to the radial-velocity populations could not be tested, because of the paucity of common objects. However, compelling indications are found that one of the new proper-motion populations consists mostly of members of the young cluster NGC 2547, and the other is related to the gamma Vel cluster. Constraints on the age of the two populations, both of which appear to be only 10-35 Myr old, and their possible mutual interactions within the last 1.5 Myrs, are discussed.