Stellar wobble caused by a binary system: Can it really be mistaken as   an extra-solar planet?
  The traditional method for detecting extra-solar planets relies on measuring a small stellar wobble which is assumed to be caused by a planet orbiting the star. Recently, it was suggested that a similar stellar wobble could be caused by a close binary system (Schneider and Cabrera, 2006). Here we show that, although the effect of a close binary system can at first sight be mistaken as a planetary companion to the star, more careful analysis of the observational data should allow us to distinguish between the two effects. 
Maria H. M. Morais, Alexandre C. M. Correia