Properties of six massive binaries

We present the analysis of six massive binaries observed with the SOPHIE spectrograph mounted on the T-193 telescope of the Observatoire de Haute Provence. The spectra are collected over the orbital period of the systems and are separated with a disentangling method. The resulting spectra are analyzed by means of atmosphere models. The stellar parameters of the components of each system are determined together with the CNO surface abundances. The degree of nitrogen enrichment and carbon and oxygen depletion is compared to theoretical predictions and to results for single stars and other binary systems. We conclude that surface abundances are not modified by binarity unless mass transfer and envelope removal takes place.