Kinematics of the Young Stellar Objects associated with the Cometary Globules in the Gum Nebula

TL;DR

This study analyzes the proper motions of Young Stellar Objects in the Gum Nebula's Cometary Globules, revealing no evidence of expansion and suggesting their kinematics align with the Vela OB2 association rather than supernova-driven expansion.

Contribution

It provides the first proper motion analysis of YSOs in the Gum Nebula's CGs, challenging previous expansion hypotheses based on radial velocities.

Findings

YSOs share proper motion with Vela OB2 stars

No evidence of CG expansion from YSO proper motions

Some YSOs with high proper motions have low infrared excesses

Abstract

An analysis of proper motion measurements of the Young Stellar Objects (YSOs) associated with the Cometary Globules (CGs) in the Gum Nebula is presented. While earlier studies based on the radial velocity measurements of the CGs suggested expansion of the system of the CGs, the observed proper motion of the YSOs shows no evidence for expansion. In particular the kinematics of two YSOs embedded in CGs is inconsistent with the supernova explosion of the companion of $\zeta$ Pup about 1.5 Myr ago as the cause of the expansion of the CG system. YSOs associated with the CGs share the average proper motion of the member stars of the Vela OB2 association. A few YSOs that have relatively large proper motions are found to show relatively low infrared excesses.