In this Letter, I examine several observational trends regarding protoplanetary disks, debris disks, and exoplanets in binary systems in an attempt to constrain the physical mechanisms of planet formation in such a context. Binaries wider than about 100AU are indistinguishable from single stars in all aspects. Binaries in the 5-100AU range, on the other hand, are associated with shorter lived but (at least in some cases) equally massive disks. Furthermore, they form planetesimals and mature planetary systems at a similar rate as wider binaries and single stars, albeit with the peculiarity that they predominantly produce high-mass planets. I posit that the location of a stellar companion influences the relative importance of the core accretion and disk fragmentation planet formation processes, with the latter mechanism being predominant in binaries tighter than 100AU.

Cone search capability for table J/ApJ/709/L114/table1 (Sample of Taurus and Ophiuchus protoplanetary disks considered in this study)