(due to my lack of english please forgive some mistakes and inaccuracy in terms and explanations. if you can rephrase and make it more accurate feel free to do that)
as we all know planets usually are part of some planetary system with one or more suns, so my idea is to make them in game.
1.mission which unlocks possibility to create sun and planetary system it self (should be relatively easy, so guys with rank 100 can actually do it) (mission must be repeatable every 100ranks)
2.Sun needs to be created (possibly drop from mission above) (possibly sun must be made out of Volcanic or Gas planets(dont really know how that should work) but planet must remain some income, if not some new one)
3.you can make 1 planetary system each 100 ranks (starting from rank 100)
4.planetary system can contain maximum of 10 planets (so you cant push all your planets in systems) in case planet is stolen from you/system it falls out of it(if you retake it, you need to tag it back if you want) to pull out planet from planetary system you need to pay same 5 GP just like Abandon Colony
5.planets which are in system have bonus of 10% to all stats (it can be divided or some certain planetary systems can contain different bonus)
6. once you have created The Sun, you have to tag planets to your planetary system. it occupies your ship for say 12h, while you are in that action you cant participate in any battles apart of NPCing, you are off the Battle tab, you cant be attacked nor you can attack, and you cant participate in base fights, if you have invaded for last 24h you cant tag the planet to Planetary system(so you cant hide behind it after planet theft)
P.S. if any additions, feel free to post them
Thanks for your attention!
Edited with red
and if its in CTlab it means it will be repeatable... which will mean you can push all you planets under the System... which is not really my basic idea, its more like chance to get the game wrong and hope that somebody will nick your planet to free up space in you solar system