  Numerous previous studies have investigated the phenomenon wherein initially
spherical N-body systems are distorted to triaxial shapes. We report on an
investigation of a previously described orbital instability that should oppose
triaxiality. After verifying the instability with numerical orbit integrations
that extend the original analysis, we search for evidence of the instability in
N-body systems that become triaxial. Our results highlight the difficulty in
separating dynamical process from finite-N effects. While we argue that our
analysis points to the presence of the instability in simulated triaxial
systems, discreteness appears to play a role in mimicking the instability. This
suggests that predicting the shapes of real-world systems, such as dark matter
halos around galaxies, based on such simulations involves more uncertainty than
previously thought.

Astrophysics of Galaxies