I never thought about this till the other day, but why did Palpatine set a trap for the Seperatists leaders on a volcanic planet? He was planning to have Vader go and kill them sooner or later. So why not pick a less dangerous planet? Clearly he didnt want Obi-Wan to duel with him there because Obi was supposed to be killed during Order 66, but doesnt a volcanic planet just sound dangerous for your apprentince? I think Nute Gunray was smart when he questioned Grievous comment of saying they are being sent to Mustafar, where they'll be safe. Logically it was a poor planet choice for Palpatine.......but cinematically it makes sense. Palpatine = The Devil, The Devil lives in hell. The steriotypical version of hell is fire all around, all the time. So the only thing natural that could look like that is a planet of volcanoes! Sure a sun/star is nothing but lava, but thats too hot! Or maybe I'm wrong and Palpatine wanted Anakin to get burned up a little so he wouldnt be too powerful and overthrow him anytime soon. Maybe ol'Sidious saw this far in the future and realized everything would be A OK, in the sense the Vader doesnt completely die! But I guess he didnt see far enough into the future to know that Vader would chuck him down an air vent.....reactor......thingy!