A PHYSICAL MODEL FOR THE IRAS ZODIACAL DUST BANDS

We present a model, based on justifiable physical assumptions, of the zodiacal cloud and asteroidal dust bands which gives a good representation of the thermal IR emission from interplanetary dust observed using IRAS. In addition to the narrow asteroidal bands that have been previously reported, we find a broad double-band component with peak intensities at beta almost-equal-to +/- 9-degrees, which shows significant emission at latitudes \beta\ approximately 20-degrees. The physical significance of this feature within the Solar system and its relationship to the zodiacal cloud are discussed.