Prospects for planet formation in multiple stellar systems

As I review here, planet formation in multiple stellar systems is far from exceptional. However, it appears that binaries with projected separation in the 5-100 AU range have different initial conditions and end result properties than wider systems, probably because they undergo different physical processes. In addition, very tight binaries, with projected separation less than a few AU, seem to fulfill all the known requirements to form planetary systems, suggesting that circumbinary planets are very likely to exist.