Dust ejection from (pre-)planetary bodies by temperature gradients: Radiative and heat transfer

Abstract

It has recently been shown that the illumination of dust beds in a low-pressure gaseous environment can generate massive ejections of dust if the light source is turned off. This effect might explain dust entrainment into the atmosphere of Mars and might destroy dusty planetesimals in protoplanetary discs. As ejection mechanism we consider compression of gas by thermal creep through the pores of the dust bed (Knudsen compressor). To approach this problem quantitatively we combine theoretical calculations of radiative and heat transfer with laboratory experiments. In this work we focus on the theoretical aspect and numerical modelling of irradiated surfaces. Temperature gradients calculated and pressure differences established by Knudsen compression are in general agreement to the threshold necessary to eject particles. © 2010 The Authors. Journal compilation © 2010 RAS.