A Particulate Thermophysical Model of the Lunar Soil

Calculations based on several thermophysical models of the lunar soil are compared with recent ob- servations at far-infrared wavelengths; none of the models reproduces simultaneously the measurements of ~unation-nighttime and eclipse cooling. A new particulate thermophysical model of the lunar soil is described which utilizes results from the Surveyor spacecraft and from laboratory experiments with evacuated powders. The new model gives good agreement with both lunation and eclipse data in the far- infrared and is consistent with measurements of lunar brightness temperatures at millimeter wavelengths. Particulate models are also used to determine the diurnal variation of the infrared surface-brightness temperature of the "hot pole" of Mercury