J/A+A/606/L3 Barnard 1b CO, NH2D and SO images (Fuente+, 2017)
Chemical segregation in the young protostars Barnard 1b-N and S:
Evidence of pseudo-disk rotation in Barnard 1b-S.
Fuente A., Gerin M., Pety J., Commercon B., Agundez M., Cernicharo J.,
Marcelino N., Roueff E., Lis D.C., Wootten H.A.
<Astron. Astrophys. 606, L3 (2017)>
=2017A&A...606L...3F 2017A&A...606L...3F (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Interferometry
Keywords: astrochemistry - ISM: clouds - ISM: individual objects: Barnard 1b -
stars: formation - stars: low mass - ISM: kinematics and dynamics
Abstract:
The extremely young Class 0 object B1b-S and the first hydrostatic
core (FSHC) candidate, B1b-N, provide a unique opportunity to study
the chemical changes produced in the elusive transition from the
prestellar core to the protostellar phase. We present 40"x70" images
of Barnard 1b in the 13CO 1-0, C18O 1-0, NH2D 1(1,1)a-1(0,1)s,
and SO 3(2)-2(1) lines obtained with the NOEMA interferometer. The
observed chemical segregation allows us to unveil the physical
structure of this young protostellar system down to scales of ∼500au.
The two protostellar objects are embedded in an elongated
condensation, with a velocity gradient of ∼0.2-0.4m/s/au in the
east-west direction, reminiscent of an axial collapse. The NH2D data
reveal cold and dense pseudo-disks (R∼500-1000au) around each
protostar. Moreover, we observe evidence of pseudo-disk rotation
around B1b-S. We do not see any signature of the bipolar outflows
associated with B1b-N and B1b-S, which were previously detected in
H2CO and CH3OH, in any of the imaged species.The non-detection of
SO constrains the SO/CH3OH abundance ratio in the high-velocity gas.
Description:
Integrated intensity images (NOEMA+30m) of the 13CO 1-0, C18O 1-0,
SO 3(2)-2(1) and NH2D 1(1,1)a-1(0,1)s lines. Units are K.km/s. These
images are shown in Fig. 1.
Objects:
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RA (2000) DE Designation(s)
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03 33 20.32 +31 07 21.5 Barnard 1b = [HKM99] B1-b
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 80 4 List of fits images
fits/* . 4 Individual fits images
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See also:
J/A+A/577/L2 : Barnard 1b-N and 1b-S nascent bipolar outflows (Gerin+, 2015)
J/A+A/606/A35 : Barnard 1b-N and 1b-S 350GHz images (Gerin+, 2017)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 30 I3 Kibyte size Size of FITS file
32- 40 A9 --- FileName Name of FITS file, in subdirectory fits
42- 80 A39 --- Title Title of the FITS file
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Acknowledgements:
Asuncion Fuente, a.fuente(at)oan.es
(End) Asuncion Fuente [OAN, Spain], Patricia Vannier [CDS] 26-Sep-2017