If you're playing as Advent you can build a Starbase in the other stars and put Evangelization Nodes on them, letting your culture spread from the Starbase. That's one way to help get a foothold culture wise in another star system. Plus as a bonus if you put a trade node there you can spread your trade route between stars for an income boost. (And if you're playing the AI, build a ton of strikecraft and laugh as the AI has no idea whatsoever how to deal with it.)
Not the case.. this is a favoured tactic of mine on multi-star maps. However, the AI will happily spam endless amounts of Torpedo Cruisers or starfish to manhandle your starbases... not to mention they usually come packing with a fleet, too, including a Titan.
With four stars and being actively engaged with your fleet elsewhere, it's easy to lose track of your starbases and see if they're getting hit.