  A new opacity model based on the Super-Transition-Array (STA) method for the
calculation of monochromatic opacities of local thermodynamic equilibrium
plasmas, was developed. The atomic code, named STAR (STA-Revised), is described
and used to calculate spectral opacities for a solar model implementing the
recent AGSS09 composition. Calculations are carried throughout the solar
radiative zone. The relative contributions of different chemical elements and
atomic processes to the total Rosseland mean opacity are analyzed in detail.
Monochromatic opacities and charge state distributions were compared with the
widely used Opacity-Project (OP) code, for several elements near the
radiation-convection interface. STAR Rosseland opacities for the solar mixture
show a very good agreement with OP and the OPAL opacity code, throughout the
radiation zone. Finally, an explicit STA calculation of the full AGSS09
photospheric mixture, including all heavy metals was performed. It was shown
that due to their extremely low abundance, and despite being very good photon
absorbers, the heavy elements do not affect the Rosseland opacity.
