Stellar wobble in triple star systems
  The radial velocity method for detecting extra-solar planets relies on measuring the star's wobble around the system's center of mass. Since this is an indirect method, we may ask if there are other dynamical effects that can mimic such wobble. In recent articles\cite{1,2,3}, we modeled the effect of a nearby binary system on a star's radial velocity. We showed that, if we are unaware of this nearby binary, for instance because one component is unresolved or both components are faint stars, the binary's effect may mimic a planet. Here, we review this work, explaining in which circumstances the binary's effect may mimic a planet and we discuss what can be done in practice in order to distinguish between these two scenarios (planet or nearby binary). 
M. H. M. Morais and A. C. M. Correia
astro-ph.EP