2004A&A...427..245S

We have imaged two bona-fide brown dwarfs with TReCS/GEMINI-S and find mid-infrared excess emission that can be explained by optically thick dust disk models. In the case of the young (≃2Myr) Cha Hα1 we measure fluxes at 10.4µm and 12.3µm that are fully consistent with a standard flared disk model and prominent silicate emission. For the ≃10Myr old brown dwarf 2MASS1207-3932 located in the TW Hydrae association we find excess emission at 8.7µm and 10.4µm with respect to the photosphere, and confirm disk accretion as a likely cause of its strong activity. Disks around brown dwarfs likely last at least as long as their low-mass stellar counterparts in the T-Tauri phase. Grain growth, dust settling, and evolution of the geometry of brown dwarf disks may appear on a timescale of 10Myr and can be witnessed by observations in the mid-infrared.