Binary stars in moving groups

Precise determination of dynamical masses of pre-main-sequence (PMS) stars is necessary to calibrate PMS stellar evolutionary models, whose predictions are in disagreement with measurements for masses below 1.2M⊙. Binary stars in young, nearby loose associations are particularly good candidates, since all members share a common age. We present phase-reference EVN observations of the binary system HD 160934 A/c, that belongs to the ABDoradus moving group, from which we have measured both the relative and absolute orbital motion. Accordingly, we obtained precise estimates of the mass of the components of this binary. Also we report on other PMS binary systems as EKDra and AB DorB. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence