What new insight did Bidong Zhang's research reveal about our solar system's early formation?

Bidong Zhang's research revealed that our solar system likely formed as a toroidal (donut-shaped) cloud of material rather than a flat disk with concentric rings. This discovery is based on studying iron meteorites from the outer solar system that contain refractory metals like platinum and iridium, which can only form in hot environments near a forming star. These metal-rich asteroids must have originated close to the sun and migrated outward as the protoplanetary structure expanded. The toroidal shape would have facilitated the movement of these metal-rich objects to the outer regions, explaining their current distribution in ways that traditional disk models cannot.