We investigate the structure of the core surrounding the recently identified deeply embedded young stellar object Barnard 1c which has an unusual polarization pattern as traced in submillimeter dust emission .
Barnard 1c lies within the Perseus molecular cloud at a distance of 250 pc .
It is a deeply embedded core of 2.4 M _ { \odot } ( Kirk et al . )
and a luminosity of 4 \pm 2 L _ { \odot } .
Observations ( and resolutions ) of ^ { 12 } CO J = 1 - 0 Â ( 9.2″Â \times 5.9″ ) , ^ { 13 } CO J = 1 - 0 Â and C ^ { 18 } O J = 1 - 0 Â ( 14.3″Â \times 6.7″ ) , HCO ^ { + } J = 1 - 0 Â ( 7.6″Â \times 5.8″ ) , and N _ { 2 } H ^ { + } J = 1 - 0 Â ( 5.9″Â \times 4.6″ ) were obtained with the Berkeley-Illinois-Maryland Association array , together with the continuum at 3.3 mm ( 6.4″Â \times 4.9″ ) and 2.7 mm ( 9.5″Â \times 6.3″ ) .
The field of view of the BIMA array antennas at 3 mm is 2.1′ .
Single-dish measurements of N _ { 2 } H ^ { + } J = 1 - 0 Â and HCO ^ { + } J = 1 - 0 Â with FCRAO reveal the larger scale emission in these lines with resolutions of 57.5″Â and 60.5″ , respectively .
The ^ { 12 } COÂ and HCO ^ { + } Â emission traces the outflow extending over the full field of view , which coincides in detail with the S-shaped jet recently found in Spitzer IRAC imaging .
The N _ { 2 } H ^ { + } Â emission , which anticorrelates spatially with the C ^ { 18 } O J = 1 - 0 Â emission , originates from a rotating envelope with effective radius \sim 2400 AU and mass 2.1 - 2.9 M _ { \odot } , as derived from the 3.3 mm continuum emission .
N _ { 2 } H ^ { + } Â emission is absent from a 600Â AU diameter region around the young star , offset from the continuum peak .
The remaining N _ { 2 } H ^ { + } Â emission may lie in a coherent torus of dense material .
With its outflow and rotating envelope , B1c closely resembles the previously studied object L483-mm , and we conclude that it is a protostar in an early stage of evolution , i.e. , Class 0 or in transition between Class 0 and Class I .
We hypothesize that heating by the outflow and star has desorbed CO from grains which has destroyed N _ { 2 } H ^ { + } Â in the inner region and surmise that the presence of grains without ice mantles in this warm inner region can explain the unusual polarization signature from B1c .