Joseph Armstrong, Chalmers University of Technology, Gothenburg, Sweden — November 11, 2024

Abstract
Most stars form in clusters or associations but only a small number of these groups remain bound for longer than a few million years. Once star formation has ended and the molecular gas around young stellar objects has been expelled via feedback processes, most initially bound young clusters lose most of their binding mass and begin to disperse into the galactic field.  Other processes, such as ejection of cluster members via dynamical interactions, can also influence the subsequent evolution of groups of young stars. Using precise Gaia 5-parameter astrometry in combination with radial velocities, we can analyse the kinematics of nearby young clusters in 6D.
I will present recent investigations in the literature which aim to identify signatures of cluster expansion and measure kinematic ages to probe their formation history and subsequent evolution. I will discuss the limitations of kinematic ages and compare them to other age determination methods. I will also highlight recent detections of runaway stars from young clusters, the ejection timescales of which can also be used to constrain the ages of their parent clusters.