2015ApJ...814...43K

A massive envelope and a strong bipolar outflow are the two main structures characterizing the youngest protostellar systems. In order to understand the physical properties of a bipolar outflow and the relationship with those of the envelope, we obtained a mosaic map covering the whole bipolar outflow of the youngest protostellar system L1157 with about 5" angular resolution in CO J = 2-1 using the Combined Array for Research in Millimeter-wave Astronomy. By utilizing these observations of the whole bipolar outflow, we estimate its physical properties and show that they are consistent with multiple jets. We also constrain a preferred precession direction. In addition, we observed the central envelope structure with 2" resolution in the and 3 mm continua and various molecular lines: C¹⁷O, C¹⁸O, ¹³CO, CS, CN, N₂H⁺, CH₃OH, H₂O, SO, and SO₂. All of the CO isotopes and CS, CN, and N₂H⁺ have been detected and imaged. We marginally detected the features that can be interpreted as a rotating inner envelope in C¹⁷O and C¹⁸O and as an infalling outer envelope in N₂H⁺. We also estimated the envelope and central protostellar masses and found that the dust-opacity spectral index changes with radius.