SIMBAD references

We present Spitzer/IRAC and MIPS 24 µm observations for 28 brown dwarfs in the Upper Scorpius (UppSco) region. We find a disk fraction of 10.7%^+8.7%_–3.3%. One object shows a small excess at 24 µm but none at shorter wavelengths, and may be a candidate transition disk. Three objects show emission in the 10 µm silicate feature and we present compositional fits for these sources. Flat structures are observed for all disk sources in UppSco. Also presented are the MIPS/70 µm observations for the TW Hydrae Association brown dwarf 2MASS J1139511-315921. We discuss the structure and chemistry of brown dwarf disks at ages of ∼5-10 Myr, and consider the possible effects of the brown dwarf densities in these clusters on the disk lifetimes.