Our previous work on planet-induced vortices has shown that the dust asymmetries associated with these vortices should be long-lived enough that they should be common in mm/sub-mm observations of protoplanetary discs. Observed asymmetries also have a variety of different azimuthal extents even though our past work has shown they should be preferentially elongated with extents around 120 to 180 degrees. We use 2-D and 3-D simulations to test whether those dust asymmetries should be so long-lived or so elongated. With higher resolution, we find that vortices can be more compact by developing compact cores when higher-mass planets cause them to re-form, or if they are seeded by tiny compact vortices from the vertical shear instability (VSI), but not through dust feedback as had previously been found. Any case with a compact vortex or compact core(s) also has a long, if not indefinite dust asymmetry lifetime. Even elongated vortices can have longer lifetimes with higher-mass planets, and if the associated planets are allowed to migrate in particular, the dust asymmetry can stop decaying as the planet migrates away from the vortex. These longer dust asymmetry lifetimes are even more inconsistent with observations, perhaps suggesting that discs still have an intermediate amount of viscosity.
[Poster PDF File]