A substellar-mass protostar and its outflow of IRAS 15398-3359 revealed by subarcsecond-resolution observations of H2CO and CCH.

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Oya, Y.
Sakai, N.
Sakai, T.
Watanabe, Y.
Hirota, T.
van Dischoeck, E.F.
Yamamoto, S.
(2014)
Astrophysical Journal, 795, 152

Subarcsecond (0".5) images of H2CO and CCH line emission have been obtained in the 0.8 mm band toward the low-mass protostar IRAS 15398−3359 in the Lupus 1 cloud as one of the Cycle 0 projects of the Atacama Large Millimeter/Submillimeter Array. We have detected a compact component concentrated in the vicinity of the protostar and a well-collimated outflow cavity extending along the northeast–southwest axis. The inclination angle of the outflow is found to be about 20, or almost edge-on, based on the kinematic structure of the outflow cavity. This is in contrast to previous suggestions of a more pole-on geometry. The centrally concentrated component is interpreted by use of a model of the infalling rotating envelope with the estimated inclination angle and the mass of the protostar is estimated to be less than 0.09 M . Higher spatial resolution data are needed to infer the presence of a rotationally supported disk for this source, hinted at by a weak high-velocity H2CO emission associated with the protostar.