dearest armorilly,
you must be psychic becuase this week I had a total freak out about brown dwarfs, planets, red giants and also those "planets" that seem to be in between brown dwarves and planets in size, yet they are alone in outer space. Normally a star, to be considered a star has to be about 20 times the size of jupiter but these things are not that big yet there they are. The roulette wheel of orbit may very well have flung them out there, who knows. I am still having problems with the concept of the solar system as a sieve where the heavier elements gravitated closer to the sun to form planets while the outer planets may be made of light gases. I don't understand this at all considering the sun is made up of aprox 75%hydrogen and 25%helium mainly with a little bit of nitrogen and other elements, the lightest element. I think the problem lays with my understanding of fusion.  I think tungsten is the heaviest element with the highest melting point so I think I would rather the sun was made out of this in order to fit into my concept of the sieve theory. Of course I have no idea what I am talking about so its no wonder the sun is not made of tungsten. 
You know alot more about this than I do so please write me and tell me what you think and if I am totally off base. Oh yeah I founda great picture of the obliquity of the planets and this has gotten me started thinking too about the formation of the thin atmospheres of Neptune and Uranus compared to the 1000 mile thick ones of Jupiter.
-Quarto