Weakly mass-loaded accretion discs

Abstract

Accretion disks with an additional mass input on the disk surface from environment are considered in the limit of low mass input rate, i.e. when the accretion flow remains keplerian. Due to dissipation of kinetic energy of the infalling gas disk temperature increases, and can deviate significantly from standard temperature of reprocessing accretion disks in their outer regions. This increase in temperature produces an excess of emission in a long-wavelength range of the disk spectrum. An illustrative example of the spectrum of a weakly mass-loaded disk (the surface mass input rate Mdot_{load} ~= 1.5 times 10^{-8} Msun yr^{-1}) reasonably reproducing FIR excess observed in CS Chameleon is given.