ICARUS 127, 461±484 (1997) ARTICLE NO. IS975704 The Three-Dimensional Structure of the Zodiacal Dust Bands William T. Reach Universities Space Research Association and NASA Goddard Space Flight Center, Code 685, Greenbelt, Maryland 20771, and Institut d'Astrophysique Spatiale, BaÃtiment 121, Universite Paris XI, 91405 Orsay Cedex, France E-mail:
[email protected] Bryan A. Franz General Sciences Corporation, NASA Goddard Space Flight Center, Code 970.1, Greenbelt, Maryland 20771 and Janet L. Weiland Hughes STX, NASA Goddard Space Flight Center, Code 685.9, Greenbelt, Maryland 20771 Received July 18, 1996; revised January 2, 1997 model, the dust is distributed among the asteroid family mem- Using observations of the infrared sky brightness by the bers with the same distributions of proper orbital inclination Cosmic Background Explorer (COBE)1 Diffuse Infrared Back- and semimajor axis but a random ascending node. In the mi- ground Experiment (DIRBE) and Infrared Astronomical Satel- grating model, particles are presumed to be under the in¯uence lite (IRAS), we have created maps of the surface brightness of Poynting±Robertson drag, so that they are distributed Fourier-®ltered to suppress the smallest (, 18) structures and throughout the inner Solar System. The migrating model is the large-scale background (.158). Dust bands associated with better able to match the parallactic variation of dust-band lati- the Themis, Koronis, and Eos families are readily evident. A tude as well as the 12- to 60-mm spectrum of the dust bands. dust band associated with the Maria family is also present. The The annual brightness variations can be explained only by the parallactic distances to the emitting regions of the Koronis, migrating model.