R Barba Poster1

Multiplicity Survey on Faint Wolf-Rayet Stars
R. Barbá (Universidad de La Serena), N.R. Walborn, and M. Sewilo

In this research we have undertaken an observational survey of galactic Wolf-Rayet stars, fainter than magnitude V=12 and with little or no information about their binarity. The study is based on optical spectra obtained between 2008 and 2013 at CTIO, Gemini South and CASLEO. We have also included data obtained at CASLEO and CTIO between 1997 and 2007. We analyzed 552 spectra, searching for variations, which may indicate the presence of binaries. In those cases where binary systems (SB1 or SB2) were detected, we have derived their orbital elements and estimated the minimum masses of the components. In a few binaries, for the first time, we have identified absorption lines belonging to a O-type star companion. In the analysis of these systems we have applied a disentangling techniques to obtain the individual spectrum for each component. This made possible to classify the previously unknown secondary component for the first time. In two SB2 systems, WR62a and WR68a, we have detected photometric variations related to eclipses of the components.