Sublimation of Interplanetary Dust

Abstract

AbstractThree topics are briefly reviewed to examine evidence for the nature of dust grains and grain alteration by physical processes related to mainly sublimation. Namely, (1) a change of dust flux detected by in situ dust measurements beyond ~ 2 AU from the Sun suggests a disappearance of volatile ices due to sublimation below this distance, (2) an elongation angle dependence of Doppler shifts observed in the zodiacal light can be explained by the introduction of a dependence of the orbital velocity on the radiation pressure forces acting on the grains, taking into account a variation of dust structure with heliocentric distance, and (3) the variation of color temperature observed in cometary coma suggests a loss of carbon content from cometary dust grains due to sublimation. This piece of evidence agrees with the generation of carbon-bearing molecules from extended sources, as infered from observations in cometary comae.