User blog comment:Scrawland Scribblescratch/I Want You! (To Help Us Answer This Question!)/@comment-1630894-20121021022006

I am leaning towards 3. This is because Phoebius and Diana are already associated with the sun and moon respectively, so it would seem wierd for them to be the name of a planet. 4 makes me think of the word "nemesis", aka enemy.

For number 3, make it Fortuna, not Tyche. All the other planets are named after Roman gods, having one be Greek would be abnormal. Plus Fortuna sounds better.