A Pseudodisk Threaded with a Toroidal and Pinched Poloidal Magnetic Field Morphology in the HH 211 Protostellar System. (arXiv:1905.09417v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Lee_C/0/1/0/all/0/1">Chin-Fei Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kwon_W/0/1/0/all/0/1">Woojin Kwon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jhan_K/0/1/0/all/0/1">Kai-Syun Jhan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hirano_N/0/1/0/all/0/1">Naomi Hirano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hwang_H/0/1/0/all/0/1">Hsiang-Chih Hwang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lai_S/0/1/0/all/0/1">Shih-Ping Lai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ching_T/0/1/0/all/0/1">Tao-Chung Ching</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rao_R/0/1/0/all/0/1">Ramprasad Rao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ho_P/0/1/0/all/0/1">Paul T.P. Ho</a>
The HH 211 protostellar system is currently the youngest Class 0 system found
with a rotating disk. We have mapped it at ~ 50 au (0.16″) resolution, studying
its magnetic field morphology with dust polarization in continuum at 232 and
358 GHz and its kinematics in C18O J=2-1 line. A flattened envelope extending
out to ~ 400 au from the disk is detected in the continuum and C18O, slightly
misaligned with the disk by 8 degree. It is spiraling inwards and expected to
transform into a rotating disk at ~ 20 au, consistent with the disk radius
estimated before. It appears to have a constant specific angular momentum and
itself can result from an inside-out collapse of an extended envelope detected
before in NH$_3$. In the flattened envelope, the polarization is mainly due to
the magnetically aligned dust grains, inferring a highly pinched poloidal field
morphology there. Thus, both the kinematics and field morphology support that
the flattened envelope is a pseudodisk formed as the infalling gas is guided by
the field lines to the equatorial plane. Interestingly, a point symmetric
polarization distribution is also seen in the flattened envelope, implying that
the pinched field lines also have a significant toroidal component generated by
the rotation. No significant loss of angular momentum and thus no clear
magnetic braking are detected in the flattened envelope around the disk
probably because of the large misalignment between the axis of the rotation and
the axis of the magnetic field in the cloud core.
The HH 211 protostellar system is currently the youngest Class 0 system found
with a rotating disk. We have mapped it at ~ 50 au (0.16″) resolution, studying
its magnetic field morphology with dust polarization in continuum at 232 and
358 GHz and its kinematics in C18O J=2-1 line. A flattened envelope extending
out to ~ 400 au from the disk is detected in the continuum and C18O, slightly
misaligned with the disk by 8 degree. It is spiraling inwards and expected to
transform into a rotating disk at ~ 20 au, consistent with the disk radius
estimated before. It appears to have a constant specific angular momentum and
itself can result from an inside-out collapse of an extended envelope detected
before in NH$_3$. In the flattened envelope, the polarization is mainly due to
the magnetically aligned dust grains, inferring a highly pinched poloidal field
morphology there. Thus, both the kinematics and field morphology support that
the flattened envelope is a pseudodisk formed as the infalling gas is guided by
the field lines to the equatorial plane. Interestingly, a point symmetric
polarization distribution is also seen in the flattened envelope, implying that
the pinched field lines also have a significant toroidal component generated by
the rotation. No significant loss of angular momentum and thus no clear
magnetic braking are detected in the flattened envelope around the disk
probably because of the large misalignment between the axis of the rotation and
the axis of the magnetic field in the cloud core.
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