Formation and Evolution of the Dust in Galaxies. I. The Condensation
  Efficiencies
  The growing interest in the high-z universe, where strongly obscured objects
are present, has determined an effort to improve the simulations of dust
formation and evolution in galaxies. Three main basic ingredients enter the
problem influencing the total dust budget and the mixture of the dust grains:
the types and amounts of dust injected by AGB stars and SNae and the
accretion/destruction processes of dust in the ISM. They govern the relative
abundances of the gas and dust in the ISM. In this study, we focus on star-dust
and present a database of condensation efficiencies for the refractory elements
C, O, Mg, Si, S, Ca and Fe in AGB stars and SNae that can be easily applied to
the gaseous ejecta, in order to determine the amount and kind of refractory
elements locally embedded into dust and injected into the ISM. The best
theoretical recipes available nowadays in literature to estimate the amount of
dust produced by SNae and AGB stars have been discussed and for SNae compared
to the observations to get clues on the problem. The condensation efficiencies
have been analyzed in the context of a classical chemical model of dust
formation and evolution in the Solar Neighbourhood and Galactic Disk. Tables of
coefficients are presented for (i) AGB stars at varying the metallicity and
(ii) SNae at varying the density n_H of the ISM where the SNa explosions took
place. In particular, we show how the controversial CNT approximation widely
adopted to form dust in SNae, still gives good results and agrees with some
clues coming from the observations. A new generation of dust formation models
in SNae is however required to solve some contradictions recently emerged. A
simple database of condensation efficiencies is set up to be used in chemical
models including the effect of dust and meant to simulate galaxies going from
primordial proto-galaxies to those currently seen in the local universe.
