What are these symbols on the System Map?

[Piratescribe]

What are these blue crescents around some of the moons (but not all of them)?
And the blue crescent with 3 lines coming off the top?
And the brackets that connect a couple of pairs of moons together?

 

[[PS4] Lorenzo Waringos]

You can land on the ones with the blue bits.

 

[[PS4] Lorenzo Waringos]

Not sure what the wiggles are on that one though. Never noticed it before. If you click on it, that panel on the left might give you a clue.

 

[Sapporo]

What are these blue crescents around some of the moons (but not all of them)?

You can land on those

And the blue crescent with 3 lines coming off the top?

There is one or more station(s) on the surface

And the brackets that connect a couple of pairs of moons together?

They are binary moons, they basically orbit each other around an invisible point in space called a barycenter.