The Gaia-ESO Survey: N-body modelling of the Gamma Velorum cluster
Abstract
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-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.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 2015
- DOI:
- 10.1051/0004-6361/201425514
- arXiv:
- arXiv:1504.02484
- Bibcode:
- 2015A&A...578A..35M
- Keywords:
-
- methods: numerical;
- open clusters and associations: individual: Gamma Velorum cluster;
- stars: formation;
- stars: kinematics and dynamics;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 12 pages, 7 figures, 2 tables, Astronomy and Astrophysics, in press