Runaway Young Stars in the Orion Nebula

TL;DR

This study uses Gaia DR2 data to identify young stars in the Orion Nebula with high proper motions, indicating recent dynamical ejections from the cluster, revealing insights into stellar interactions in young clusters.

Contribution

It presents the first systematic search for high proper motion young stars in the Orion Nebula, linking their origins to dynamical interactions within the cluster.

Findings

26 candidate runaway stars identified

9 traced back to the Trapezium cluster

Ejection events likely occur within the last 1 million years

Abstract

The star forming region of the Orion Nebula (ONC) is ideal to study the stellar dynamics of young stars in a clustered environment. Using Gaia DR2 we search for the pre-main sequence stars with unusually high proper motions that may be representative of a dynamical ejection from unstable young triple systems or other close three-body encounters. We identify twenty-six candidate stars that are likely to have had such an encounter in the last 1 Myr. Nine of these stars could be traced back to the densest central-most region of the ONC, the Trapezium, while five others have likely interactions with other OB-type stars in the cluster. Seven stars originate from other nearby populations within the Orion Complex that coincidentally scattered towards the ONC. A definitive point of origin cannot be identified for the remaining sources. These observations shed light on the frequency of the ejection events in young clusters.