What's the theory for the formation of exo-planets?
Well, it seems the short answer is: "not by the accretion of gases/elements". However, I've seen numerous articles online regarding this subject that might be more helpful to you. Here's a Google link:
Although the first page is mostly 2012 articles about the same "odd couple" exoplanets, further into the other search pages, there are various other articles from 2010, 2005, etc about different exoplanets that also defy current models of planet formation. Also, I imagine other similar key word searches would yield additional results.
That said, however, it all really depends on how far down the rabbit hole you want to go, because the generally accepted planetary formation theory is based on the veracity of the Big Bang theory, a leaky, patched-up boat that doesn't really seem to be sea-worthy anymore, especially as it now requires 96% of the universe to be made up of magical, imaginary substances like dark matter/energy...
Post Edited (29-Jan-13 03:11)