MULTIWAVELENGTH STUDY OF THE POWERING SOURCES OF THE DOUBLE H_2 BIPOLAR JET IN L1634

摘要

We present observations of the centimeter, millimeter, and submillimeter continuum emission toward the core of L1634, a region with two embedded young stellar objects, IRAS 05173-0555 and IRS 7, which are powering two outflows. The submillimeter dust emission around IRAS 05173-0555 is resolved and shows two components, a centrally peaked source plus a considerably extended envelope, while the emission around IRS 7 appears unresolved with an angular resolution of ～ 8″. The dust emiss-ivity index, derived from the submillimeter spectral index, is β ～ 1.8 fpr both embedded sources, implying that the properties of the dust are similar around both objects. The submillimeter spectral index varies throughout the region, with lower values found toward the'compact embedded sources, likely indicating grain growth on small scales. The high quality of the 850 and 450 μm continuum maps allows us to fit the radial intensity profiles of the extended emission around IRAS 05173-0555 with a power-law model that constrains the density distribution. The best fit to the data is a model with a multiple power-law density distribution, with slopes consistent with the predictions of the inside-out protostellar collapse model. We derive an infall rate of (2.6-8.0) x 10~(-5) solar mass yr~(-1) for the free-falling inner region of the envelope. The submillimeter luminosity, the total circumstellar mass derived, and the infall rate estimate are consistent with IRAS 05173-0555 being a Class 0 object.