  Understanding the history and evolution of small bodies, such as dust grains
and comets, in planet-forming disks is very important to reveal the
architectural laws responsible for the creation of planetary systems. These
small bodies in cold regions of the disks are typically considered as mixtures
of dust particles with molecular ices, where ices cover the surface of a dust
core or are actually physically mixed with dust. Whilst the first case,
ice-on-dust, has been intensively studied in the laboratory in recent decades,
the second case, ice-mixed-with-dust, present uncharted territory. This work is
the first laboratory study of the temperature-programmed desorption (TPD) of
water ice mixed with amorphous carbon and silicate grains. We show that the
kinetics of desorption of H2O ice depends strongly on the dust/ice mass ratio,
probably, due to the desorption of water molecules from a large surface of
fractal clusters composed of carbon or silicate grains. In addition, it is
shown that water ice molecules are differently bound to silicate grains in
contrast to carbon. The results provide a link between the structure and
morphology of small cosmic bodies and the kinetics of desorption of water ice
included in them.

Astrophysics of Galaxies