Known members of Orion A with Gaia DR2 data

Using Gaia DR2 we search for 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 26 candidate stars that are likely to have had such an encounter in the last 1Myr.

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 toward the ONC. A definitive point of origin cannot be identified for the remaining sources.