  (abridged) We present STARDUST, a new self-consistent modelling of the
spectral energy distributions (SEDs) of galaxies from far-UV to radio
wavelengths. In order to derive the SEDs in this broad spectral range, we first
couple spectrophotometric and (closed-box) chemical evolutions to account for
metallicity effects on the spectra of synthetic stellar populations. We then
use a phenomenological fit for the metal-dependent extinction curve and a
simple geometric distribution of the dust to compute the optical depth of
galaxies and the corresponding obscuration curve. This enables us to calculate
the fraction of stellar light reprocessed in the infrared range. In a final
step, we define a dust model with various components and we fix the weights of
these components in order to reproduce the IRAS correlation of IR colours with
total IR luminosities. This allows us to compute far-IR SEDs that
phenomenologically mimic observed trends. We are able to predict the spectral
evolution of galaxies in a broad wavelength range, and we can reproduce the
observed SEDs of local spirals, starbursts, luminous infrared galaxies (LIRGs)
and ultra luminous infrared galaxies (ULIRGs). This modelling is so far kept as
simple as possible and depends on a small number of free parameters, namely the
initial mass function (IMF), star formation rate (SFR) time scale, gas density,
and galaxy age, as well as on more refined assumptions on dust properties and
the presence (or absence) of gas inflows/outflows.
