Spitzer discovery of very low luminosity objects

The Spitzer Space Telescope allows for the first time to search systematically for very low luminosity (less than or similar to 0.1 L circle dot) objects (VeLLOs) associated with dense molecular cores. They may be the first candidate Class 0 sources with sub-stellar masses. We describe such a source in the dense molecular core L1148. VeLLO natal cores show properties that are unusual for star-forming cores. The low luminosity and in some cases the lack of prominent outflow could be the result of the small gas supply near the VeLLO.