Those are the nomads who try to push through the gate, so in future, there will be a new Omicron/Nomad system.
I am not sure, but this is the most probable thing that can happen.
Second one is...welll. Nomads are building up a massive Hyper Gate, leading into a place in Sirius, expanding the nomad's ZOI.
EDIT: NOW I REMEMBER!
That is the entrance to the original Dyson sphere. What we see as Omicron Major(what we can acess), is the huge barrier, where those shield generators were located. That is the entrance tk the Dyson Sphere, where Trent believed he destroyed the nomads once and for all. The system may be avalable to players again.