The origin of early-type runaway stars from open clusters

Runaway stars are ejected from their place of birth in the Galactic disk, with some young B-type runaways found several tens kiloparsecs plane traveling at speeds beyond escape velocity, which calls for violent ejection processes. Young open clusters a likely origin, and may be either through N -body interactions or binary supernova explosions. The most energetic events require dynamical interaction massive black holes. excellent quality Gaia astrometry opens up path to study kinematics runaway such high precision that origin stellar can identified uniquely even when star is few away. We developed an efficient minimization method calculate whether two more objects come same place, we tested against samples Orion runaways. Our fitting procedure was then used trajectories known stars, have previously been studied H IPPARCOS as well clusters. For our sample data updated radial velocities, only half could classified other moves so slowly (< 30 km s ?1 ) they considered walkaway stars. Most latter turned out binaries. parent based on trajectories. cluster age flight time investigate due ejection. In particular show classical AE Aurigae ? Columbae might not originated together, having earlier Collinder 69, near ONC. second investigated comprises set distant B halo carefully by quantitative spectral analyses. able identify candidate least four including hyper-runaway HIP 60350. had very violent, ejecting velocities large 150–400 .