Dynamics of triaxial galaxies with a central density cusp
  Cuspy triaxial potentials admit a large number of chaotic orbits, which moreover exhibit extreme "stickiness" that makes the process of chaotic mixing surprisingly inefficient. Environmental effects, modeled as noise and/or periodic driving, help accelerate phase space transport but probably not as much as in simpler potentials. This could mean that cuspy triaxial ellipticals cannot exist as time-independent systems. 
Christos Siopis (1 and 2) and Henry E. Kandrup (1) ((1) University of   Florida, (2) University of Michigan)