The multiplicity fraction of field stars is almost 50% . The study of exoplanets in the context of binaries is thus of crucial importance, given that binarity should be a relatively common environment. I will present the first complete census of known planet-hosting binaries, derived from intense literature and catalogue search. Our sample lists 728 systems (of which 77 are triples or quadruples) with « S-type » orbits (planet orbiting one star of a binary pair) as well as 31 circumbinary systems (« P-type » orbits).
Despite the great heterogeneity of our sources and the multiple biaises that affect the planet-hosting binary population (adverse selection effect in RV surveys, difficulty of finding close-in companions in deep imaging searches, …), I will show that some robust statistical trends can be derived. Our main result is that, contrary to what was claimed in some earlier studies, the observed depletion of planet-hosting close-in binaries (<100au) should, to a significant extent, be a real feature. Likewise, the 23% global multiplicity fraction that we derive, which is about half of the value for field stars, should be relatively reliable. These results confirm the detrimental (but not fully inhibiting !) effect that close-in companions are expected to have on the planet-formation process.
