Institute for Advanced Study/Princeton University Joint Astrophysics Colloquium

A large number of close-in super-Earths have now been discovered. These planets are most likely formed while the proto-planetary disks are still alive, hence the title of this talk. I will report some recent observational results, regarding their masses, compositions, relationship to companion planets, and to host star metallicity and binarity. A picture emerges where gen-I planets share surprisingly uniform properties. Earth and other terrestrial planets probably formed after the gaseous disks have dispersed (gen-II planets). Currently we have scant evidence for their existence in extra-solar systems. This strongly motivates new searches.