2013ApJ...771..128H

We present the results of observations toward a low-mass Class-0/I protostar [BHB2007]#11 (B59#11) in the nearby (d = 130 pc) star-forming region Barnard 59 (B59), in the Pipe Nebula. We utilize the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope (∼22'' resolution), focusing on the CO(3-2), HCO⁺, H¹³CO⁺(4-3), and 1.1 mm dust-continuum emission transitions. We also show Submillimeter Array (SMA) data with ∼5'' resolution in ¹²CO, ¹³CO, C¹⁸O(2-1), and 1.3 mm dust-continuum emission. From ASTE CO(3-2) observations, we found that B59#11 is blowing a collimated outflow whose axis lies almost on the plane of the sky. The outflow traces well a cavity-like structure seen in the 1.1 mm dust-continuum emission. The results of SMA ¹³CO and C¹⁸O(2-1) observations have revealed that a compact and elongated structure of dense gas is associated with B59#11; the structure is oriented perpendicular to the outflow axis. There is a compact dust condensation with a size of 350x180 AU seen in the SMA 1.3 mm continuum map, and the direction of its major axis is almost the same as that of the dense gas elongation. The distributions of ¹³CO and C¹⁸O emission also show velocity gradients along their major axes, which are thought to arise from the envelope/disk rotation. From detailed analysis of the SMA data, we infer that B59#11 is surrounded by a Keplerian disk with a radius of less than 350 AU. In addition, the SMA CO(2-1) image shows a velocity gradient in the outflow in the same direction as that of the dense gas rotation. We suggest that this velocity gradient indicates rotation in the outflow.