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 $\infty$-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.
