Disks in the proto-multiple stellar system IRAS 16293-2422 observed with the SMA and VLA
Authors:
          Claire Chandler, National Radio Astronomy Observatory
          Crystal Brogan, University of Hawaii
          Yancy Shirley, National Radio Astronomy Observatory

Abstract:
          We report sub-arcsecond resolution observations of the proto-multiple stellar system IRAS 16293-2422 using the Smithsonian Submillimeter Array (SMA) and the Very Large Array (VLA).  The combined capabilities of these instruments permit an extraordinarily detailed analysis of the kinematical and chemical structure of IRAS 16293 on size scales < 100 AU.  The two main components of this system, A and B, exhibit very different properties and probably represent two stages of early stellar evolution, with source A being the younger.  An analysis of archival VLA data shows that the ionized jet from source A has changed its position angle over the last 20 years, and this may be the first direct measurement of jet precession in such a young source.  Source A is also associated with copious molecular line emission more typical of massive hot cores, and at 300 GHz exhibits emission from species such as H2S, SO, and dimethyl ether.  We also report the detection of a new candid ate companion to source A, and discuss the possibility that this source is responsible for the precession of the jet.  Source B, on the other hand, exhibits a nu2 spectrum from 5 GHz to 300 GHz, which we suggest arises from an optically-thick dust disk.