Mapelli, M.M.MapelliVallenari, A.A.VallenariJeffries, R. D.R. D.JeffriesPancino, ElenaElenaPancino2020-09-172020-09-172015-04-01https://hdl.handle.net/20.500.13025/4384eprint arXiv 1504.02484The Gaia-ESO Survey has recently unveiled the complex kinematic signature of the Gamma Velorum cluster this cluster is composed of two kinematically distinct populations (hereafter, population A and B), showing two different velocity dispersions and a relative ~2 km s^-1 radial velocity (RV) shift. In this paper, we propose that the two populations of the Gamma Velorum cluster originate from two different sub-clusters, born from the same parent molecular cloud. We investigate this possibility by means of direct-summation N-body simulations. Our scenario is able to reproduce not only the RV shift and the different velocity dispersions, but also the different centroid (~0.5 pc), the different spatial concentration and the different line-of-sight distance (~5 pc) of the two populations. The observed 1-2 Myr age difference between the two populations is also naturally explained by our scenario, in which the two sub-clusters formed in two slightly different star formation episodes. Our simulations suggest that population B is strongly supervirial, while population A is close to virial equilibrium. We discuss the implications of our models for the formation of young star clusters and OB associations in the Milky Way.Astrophysics - Astrophysics of GalaxiesAstrophysics - Solar and Stellar AstrophysicsAstronomy and Astrophysicsin presshttp://adsabs.harvard.edu/abs/2015arXiv150402484M2015arXiv150402484M