Heliocentric variation of dust production in comets inferred from infrared observations

The observed infrared emission from comets has been used to derive the heliocentric dependence of the dust production rate. There is a tight relation with heliocentric distance r, showing 1/r-squared variation up to r less than about 1 AU for Comet Kohoutek and 1/r to the 4th for r greater than about 1 AU for Comet Halley. There appears to be a general pattern of behavior in the shape of the heliocentric dependence of the dust production rate for several comets. This trend is qualitatively similar to the sublimation curves for water-ice