Gas and dust from solar metallicity AGB stars

We study the asymptotic giant branch (AGB) evolution of stars with masses between 1M(circle dot)and8.5M(circle dot). We focus on stars with a solar chemical composition, which allows us to interpret evolved stars in the Galaxy. We present a detailed comparison with models of the same chemistry, calculated with a different evolution code and based on a different set of physical assumptions. We find that stars of mass >= 3.5M(circle dot) experience hot bottom burning at the base of the envelope. They have AGB lifetimes shorter than similar to 3 x 10(5) yr and eject into their surroundings gas contaminated by proton-capture nucleosynthesis, at an extent sensitive to the treatment of convection. Low-mass stars with 1.5M(circle dot) <= M <= 3M(circle dot) become carbon stars. During the final phases, the C/O ratio grows to similar to 3. We find a remarkable agreement between the two codes for the low-mass models and conclude that predictions for the physical and chemical properties of these stars, and the AGB lifetime, are not that sensitive to the modelling of the AGB phase. The dust produced is also dependent on the mass: low-mass stars produce mainly solid carbon and silicon carbide dust, whereas higher mass stars produce silicates and alumina dust. Possible future observations potentially able to add more robustness to the present results are also discussed.