  The dynamical structure and infrared emission of winds around late-type stars
are studied in a self-consistent model that couples the equations of motion and
radiative transfer. Both the dynamics and IR spectrum of the solution are fully
characterized by the flux averaged optical depth. Five types of dust grains are
considered: astronomical silicate, SiC, crystalline olivine, graphite and
amorphous carbon as well as mixtures. Analysis of infrared signatures provides
constraints on the grain chemical composition and indications for the
simultaneous existence of silicate and carbon grains. The region of parameter
space where radiation pressure can support a given mass-loss rate is identified
and a new method to derive mass loss rates from IR data is presented. IRAS LRS
classes are associated with optical depth for various grain materials and the
regions of color-color diagrams expected to be populated by late-type stars are
identified. We show that cirrus emission can severely affect point source
measurements to the extent that their listed IRAS long wavelength fluxes are
unreliable. After accounting for cirrus contamination, essentially all IRAS
point sources located in the relevant regions of the color-color diagrams can
be explained as late-type stars.
