Numerical calculations show that a long-lived, robust vortex can persist in the solar nebula.
If several negative vortices are close to each other, they will merge to form a larger vortex. A -sized particle will be mostly locked with the vortex, with a small drift component. A cm -sized particle will drift faster, reaching the middle of the vortex in about . The differential drift velocity increases the number of collisions, enhancing aggregation into larger particles.