A stellar fly-by simulation giving Beta Pic's disc asymmetries
  We have numerically investigated the dynamics of how a close stellar fly-by encounter of a symmetrical circumstellar planetesimal disc can give rise to the many kinds of asymmetries and substructures attributed to the dusty disc of Beta Pic. We find three recognizable groupings of test particles that can be related to the morphology of the Beta Pic disc. These are: highly eccentric and inclined orbit particles that reach apocentre in the southwest, moderately eccentric and inclined orbit particles that reach apocentre in the northeast, and a relatively unperturbed region inside ~200au radius. 
J. Larwood and P. Kalas