8-12 juin, 2014


Constraining massive star evolution from massive clusters

André-Nicolas Chené (Gemini North Observatory)

Anthony Herve, Fabrice Martins (Universite Montpellier II), Jean-Claude Bouret (Laboratoire d/Astrophysique de Marseille), Jordanka Borissova, Sebastian Ramirez, Radostin Kurtev, Pia Amigo, Celia Fierro (Universidad de Valparaiso) and Nanda Kumar (Centro de Astrofisica da Universidade do Porto)

The exact evolution of massive stars is not accurately known at present. The general trend is that stars with masses above 40-60 Msol go from O-type stars to H-rich WN stars, and Luminous Blue Variables (?), before turning into H-poor WN stars and finally WC stars. At lower masses, the H-rich WN and LBV phases are replaced by a blue and a red supergiant phases, respectively. However, what are the details of such evolutionary sequences? The study of massive clusters is a golden opportunity to establish this. Indeed, the turn-off mass of massive clusters can be directly translated into the mass, and hence the nature, of the progenitors of their evolved objects contents. So far, only the Arches, Quintuplet, NGC3603, NGC2244 and central clusters have been studied this way. But 6 newly discovered heavily-obscured clusters in the large survey “VISTA Variables in the Via Lactea” (VVV) have been found to have Wolf-Rayet stars as well as blue and/or red supergiants, together with many main sequence OB stars. I am briefly presenting the VVV survey before detailling our efforts to model the massive star components of these clusters using CMFGEN. This work is bringing new blocks to the pavement of massive stellar evolution and more than doubling the number of clusters in which such evolutionary sequence are established.
(doit être confirmé par le SOC)