  We use the clathrate hydrate trapping theory (Lunine & Stevenson 1985) and
the gas drag formalism of Weidenschilling (1977) to calculate the composition
of ices incorporated in the interior of Ceres. In the spirit of the work of Cyr
et al. (1998), and using a time dependent solar nebula model, we show that icy
solids can drift from beyond 5 AU to the present location of the asteroid and
be preserved from vaporization. We argue that volatiles were trapped in the
outer solar nebula under the forms of clathrate hydrates, hydrates and pure
condensates prior to having been incorporated in icy solids and subsequently in
Ceres. Under the assumption that most of volatiles were not vaporized during
the accretion phase and the thermal evolution of Ceres, we determine the per
mass abundances with respect to H2O of CO2, CO, CH4, N2, NH3, Ar, Xe, and Kr in
the interior of the asteroid. The Dawn space mission, scheduled to explore
Ceres in August 2014 (Russel et al. 2004), may have the capacity to test some
predictions. We also show that an in situ measurement of the D/H ratio in H2O
in Ceres could constrain the distance range in the solar nebula where its icy
planetesimals were produced.
