On radial motion of dense regions and objects in protoplanitary-like disks

Astronomers recently discovered a non-trivial radial motion of stars within our galaxy and were able to reproduce the results using n-body numerics. I modeled a protoplanitary-like disk within a newtonian $\mathrm{\infty }$-body problem and considered the stability of local trajectories giving a qualitative explanation to the observed radial motion. As a prospect there will be a short estimate on the impact on spiral arms.