Massive Light-Induced Ejections of Dust Particles from (pre-)Planetesimal Surfaces
Authors:
M. Kocifaj
Image & caption:
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Image caption::
Particle ejections from a JSC-Mars simulant powder upon illumination. The gas pressure here is a few mbar, the light flux (illumination from top) is a few kW/m2 decreasing from the centre to the sides. The width of the visible area is about 5 cm.
Description:
Light-induced dust eruptions from dusty layers have been observed only recently in laboratory conditions. These observations have initiated discussions on possible astrophysical consequences of this phenomenon, for example light-induced destruction of planetesimals. In our work we theoretically explained this effect and characterized the conditions under which it occurs. The principle of this phenomenon can be illustrated as follows: electromagnetic radiation penetrating the dusty layer causes its gradual heating. The activated changes of subsurface temperature lead to alteration of energy balance in the dust layer due to radiation cooling and convection. The combined effect is a temporal- and depth-dependent temperature gradient. The massive ejections of dust particles can be observed if the temperature peaks in a subsurface layer (Knudsen compressor). This effect may play important role on Mars because the atmospheric pressure at its surface is only a few millibars. Dust eruptions caused by altering irradiance are even more important for (pre-) planetesimals, which may undergo destructive effects at a long time-scale.
Reference:
Monthly Notices of the Royal Astronomical Society 404, 1512-1518 (2010)
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