ALMA RESULTS OF THE PSEUDODISK, ROTATING DISK, AND JET IN THE CONTINUUM AND HCO + IN THE PROTOSTELLAR SYSTEM HH 212

HH 212 is a nearby (400 pc) Class 0 protostellar system showing several components that can be compared with theoretical models of core collapse. We have mapped it in the 350 GHz continuum and HCO{sup +} J = 4-3 emission with ALMA at up to ∼0.''4 resolution. A flattened envelope and a comp...

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Bibliographic Details
Published in:The Astrophysical journal 2014-05, Vol.786 (2), p.114
Main Authors: Lee, Chin-Fei, Hirano, Naomi, Zhang, Qizhou, Shang, Hsien, Ho, Paul T. P., Krasnopolsky, Ruben
Format: Article
Language:English
Subjects:
ABUNDANCE
ACCRETION DISKS
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
COMPARATIVE EVALUATIONS
DENSITY
EMISSION
INTERFACES
PROTOSTARS
RED SHIFT
RESOLUTION
ROTATION
SILICON OXIDES
STARS
VELOCITY
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Summary:HH 212 is a nearby (400 pc) Class 0 protostellar system showing several components that can be compared with theoretical models of core collapse. We have mapped it in the 350 GHz continuum and HCO{sup +} J = 4-3 emission with ALMA at up to ∼0.''4 resolution. A flattened envelope and a compact disk are seen in the continuum around the central source, as seen before. The HCO{sup +} kinematics shows that the flattened envelope is infalling with small rotation (i.e., spiraling) into the central source, and thus can be identified as a pseudodisk in the models of magnetized core collapse. Also, the HCO{sup +} kinematics shows that the disk is rotating and can be rotationally supported. In addition, to account for the missing HCO{sup +} emission at low-redshifted velocity, an extended infalling envelope is required, with its material flowing roughly parallel to the jet axis toward the pseudodisk. This is expected if it is magnetized with an hourglass B-field morphology. We have modeled the continuum and HCO{sup +} emission of the flattened envelope and disk simultaneously. We find that a jump in density is required across the interface between the pseudodisk and the disk. A jet is seen in HCO{sup +} extending out to ∼500 AU away from the central source, with the peaks upstream of those seen before in SiO. The broad velocity range and high HCO{sup +} abundance indicate that the HCO{sup +} emission traces internal shocks in the jet.
ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/786/2/114