The three-dimensional (3D) distribution of zodiacal dust derived from infrared and visual measurements and their compatibility including dust dynamics

Abstract

Several different models describe the three-dimensional global behaviour of the zodiacal dust cloud. They have been derived from measurements of the thermal emission of the dust particles (infrared) and from measurements of the scattered sunlight (optical). A sufficient agreement of the infrared models with the optical models is achieved for comparison with observations at larger elongations. Close to the Sun the infrared models become, however, flattened at the poles without showing any bulge. Dynamical considerations seem to favour these flattened models because they need a lower amount of retrograde orbits. This small component of retrograde orbits is confirmed by an analysis of the Doppler-shift in the Fraunhofer-lines from sunlight scattered at zodiacal dust. The comparison of optical and infrared models shows there are more observations necessary especially in the sunward direction.