Volume 583, November 2015
|Number of page(s)||10|
|Section||Galactic structure, stellar clusters and populations|
|Published online||30 October 2015|
Institut Utinam, CNRS UMR 6213, Université de Franche-Comté, OSU THETA
Franche-Comté-Bourgogne, Observatoire de Besançon,
2 Centro de Investigaciones de Astronomía, AP 264, 5101-A Mérida, Venezuela
3 Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 70264, 04510 México D.F., Mexico
4 Observatoire astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l’Université, 67000 Strasbourg, France
5 Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ap. 70-543, 04510 D.F., México, Mexico
Received: 20 May 2015
Accepted: 10 August 2015
Using six-dimensional phase-space information from the Fourth Data release of the RAdial Velocity Experiment (RAVE) over the range of Galactic longitude 240°<l< 360° and VLSR< −239 km s-1, we computed orbits for 329 RAVE stars that were originally selected as chemically and kinematically related to ω Centauri. The orbits were integrated in a Milky-Way-like axisymmetric Galactic potential, ignoring the effects of the dynamical evolution of ω Centauri due to the tidal effects of the Galaxy disk on the cluster along time. We also ignored secular changes in the Milky Way potential over time. In a Monte Carlo scheme, and under the assumption that the stars may have been ejected with velocities greater than the escape velocity (Vrel>Vesc,0) from the cluster, we identified 15 stars as having close encounters with ω Centauri: (i) 8 stars with relative velocities Vrel< 200 km s-1 may have been ejected ~200 Myr ago from ω Centauri; (ii) another group of 7 stars were identified with high relative velocity Vrel> 200 km s-1 during close encounters, and it seems unlikely that they were ejected from ω Centauri. We also confirm the link between J131340.4-484714 as a potential member of ω Centauri, and probably ejected ~2.0 Myr ago, with a relative velocity Vrel ~ 80 km s-1.
Key words: stars: abundances / stars: kinematics and dynamics / Galaxy: structure / globular clusters: individual: ωCentauri
Appendix A is available in electronic form at http://www.aanda.org
Full Table A.1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (184.108.40.206) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/583/A76
© ESO, 2015
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