A Disk Shadow Around the Young Star ASR 41 in NGC 1333
We present images of the young stellar object ASR 41 in the NGC 1333 star forming region at the wavelengths of H_alpha and [SII] and in the I, J, H, and K-bands. ASR 41 has the near-infrared morphology of an edge-on disk object, but appears an order of magnitude larger than typical systems of this kind. We also present detailed models of the scattering and radiative transfer in systems consisting of a young star surrounded by a proto-planetary disk, and the whole system being embedded in either an infalling envelope or a uniform molecular cloud. The best fit to the observed morphology can be achieved with a disk of approx. 200 AU diameter, immersed in a low density cloud. The low cloud density is necessary to stay below the sub-mm flux upper limits and to preserve the shadow cast by the disk via single scattering. The results demonstrate that ASR 41 is probably not inherently different from typical edge-on disk objects, and that its large apparent size is due to the shadow of a much smaller disk being projected into the surrounding dusty molecular material.