The Spitzer c2d Survey of Nearby Dense Cores. IV. Revealing the Embedded Cluster in B59

Abstract

Infrared images of the dark cloud core B59 were obtained with the Spitzer Space Telescope as part of the ``Cores to Disks'' Legacy Science project. Photometry from 3.6-70 μm indicates at least 20 candidate low-mass young stars near the core, more than doubling the previously known population. Out of this group, 13 are located within ~0.1 pc in projection of the molecular gas peak, where a new embedded source is detected. Spectral energy distributions span the range from small excesses above photospheric levels to rising in the mid-infrared. One other embedded object, probably associated with the millimeter source B59-MMS1, with a bolometric luminosity Lbol~2 Lsolar, has extended structure at 3.6 and 4.5 μm, possibly tracing the edges of an outflow cavity. The measured extinction through the central part of the core is AV>~45 mag. The B59 core is producing young stars with a high efficiency.