September 23
The Collisional Cascade Model for Saturn Ring Spokes
Speaker: Prof. Doug Hamilton, UMD ASTR
Abstract: Micron and sub-micron sized dust grains liberated from Saturn’s rings from impact of interplanetary material can explain the origin and morphology of dusty spokes in Saturn’s B ring. Sub-micron material is gently lofted from ring particles, accelerated and transported radially by electromagnetic forces, and it ultimately re-collides with the ring at speeds of several km/s. These secondary impacts are energetic enough to loft additional micron and sub-micron material into the growing spoke. The sub-micron material is invisible but continues to produce additional micron-sized material. And the micron-sized contributes directly to spoke brightnesses.