New Low-Mass Stars and Brown Dwarfs with Disks in the Chamaeleon I Star-Forming Region

We have used images obtained with the Infrared Array Camera and the Multiband Imaging Photometer onboard the Spitzer Space Telescope to search for low-mass stars and brown dwarfs with circumstellar disks in the Chamaeleon I star-forming region. Through optical spectroscopy of sources with red colors in these data, we have identified seven new disk-bearing members of the cluster. Three of these objects are probably brown dwarfs according to their spectral types (M8, M8.5, M8-L0). Three of the other new members may have edge-on disks based on the shapes of their infrared spectral energy distributions. One of the possible edge-on systems has a steeply rising slope from 4.5 to 24um, indicating that it could be a class I source (star+disk+envelope) rather than a class II source (star+disk). If so, then it would be one of the least massive known class I protostars (M5.75, M~0.1 Msun).