The Gaia -ESO Survey: N -body modelling of the Gamma Velorum cluster

The 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<sup>-1</sup> rad...

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Detalles Bibliográficos
Autores: Mapelli, M., Vallenari, A., Jeffries, R. D., Gavagnin, E., Cantat-Gaudin, T., Sacco, G. G., Meyer, M. R., Alfaro, Emilio J., Costado, M. T., Damiani, F., Frasca, A., Lanzafame, A. C., Randich, S., Sordo, R., Zaggia, S., Micela, G., Flaccomio, E., Pancino, E., Bergemann, M., Hourihane, A., Lardo, C., Magrini, L., Morbidelli, L., Prisinzano, L., Worley, C. C.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2015
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/388114
Acceso en línea:http://hdl.handle.net/10261/388114
Access Level:acceso abierto
Palabra clave:Methods: numerical
Open clusters and associations: individual: Gamma Velorum cluster
Stars: formation
Stars: kinematics and dynamics
Descripción
Sumario:The 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<sup>-1</sup> 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. © 2015 ESO.

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