IRAS 16293: A "Magnetic" Tale of Two Cores
  We present polarization observations of the dust continuum emission from IRAS
16293 which is a Class 0 protostar and is known to have at least two
components, source A and B. These measurements were conducted by the
Submillimeter Array (SMA) at a frequency of ~341 GHz and with high angular
resolution (~2-3 arcseconds). We find that the large scale global direction of
the field, which is perpendicular to the observed polarization, appears to be
along the dust ridge where the emission peaks. On smaller scales we find that
the field structure is significantly different for the two components of the
binary. The first component, source A, shows a magnetic field structure which
is "hourglass" shaped as predicted from theoretical models of low mass star
formation in the presence of strong magnetic fields. However, the other
component, source B, shows a relatively ordered magnetic field with no evidence
of any deformation. There is an observed decrease in polarization towards the
center. Our calculations show that in IRAS 16293 the magnetic energy is
stronger than the turbulent energy but is approximately similar to the
centrifugal energy. Our results provide additional evidence to show that the
two protostars appear to be in different stages during their evolution.
