Earth Planets Space, Vol. 50 (Nos. 6, 7), pp. 531-537, 1998
S. Yamamoto and T. Mukai
The Graduate School of Science and Technology, Kobe University, Nada, Kobe 657-8501, Japan
(Received November 21, 1997; Revised January 21, 1998; Accepted February 1, 1998)
Abstract: We calculate the temperature of dust grains produced in Edgeworth-Kuiper Belt (EKB) based on the grain model for water-ice and silicate mixtures. The dust grains with radii ranging from 0.1mm to 1 mm have low temperatures of about 20 K to 50 K in EKB, depending on their size, solar distance, and a volume mixing ratio of silicate to water-ice. We also estimate the thermal radiation from dust cloud in EKB. The result of thermal emission shows the spectral feature of water-ice at the wavelength of about 60mm. Although it is difficult to estimate the possibility to detect the thermal emission spectrum of EKB dust cloud, due to large uncertainties in its spatial density, we found that the thermal emission of dust cloud in EKB lies below the IRAS data of foreground zodiacal emission. The maximum value of the thermal emission derived from the acceptable dust cloud model in EKB, however, becomes to be comparable to that of foreground zodiacal emission in far-infrared and submillimeter wavelength domains. Since the EKB dust cloud seems to concentrate near the ecliptic plane, a scanning of infrared observation along a line perpendicular to the ecliptic plane may reveal the presence of such dust cloud in the future.