ALMA reveals a large structured disk and nested rotating outflows in DG Tau B. (arXiv:2001.09776v1 [astro-ph.SR])

ALMA reveals a large structured disk and nested rotating outflows in DG Tau B. (arXiv:2001.09776v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Valon_A/0/1/0/all/0/1">A. de Valon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dougados_C/0/1/0/all/0/1">C. Dougados</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cabrit_S/0/1/0/all/0/1">S. Cabrit</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Louvet_F/0/1/0/all/0/1">F. Louvet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zapata_L/0/1/0/all/0/1">L. A. Zapata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mardones_D/0/1/0/all/0/1">D. Mardones</a>

We present Atacama Large Millimeter Array (ALMA) Band 6 observations at 14-20
au spatial resolution of the disk and CO(2-1) outflow around the Class I
protostar DG Tau B in Taurus. The disk is very large, both in dust continuum
(R$_{rm eff,95%}$=174 au) and CO (R$_{CO}$=700 au). It shows Keplerian
rotation around a 1.1$pm$0.2 M$_{odot}$ central star and two dust emission
bumps at $r$ = 62 and 135 au. These results confirm that large structured disks
can form at an early stage where residual infall is still ongoing. The
redshifted CO outflow at high velocity shows a striking hollow cone morphology
out to 3000 au with a shear-like velocity structure within the cone walls.
These walls coincide with the scattered light cavity, and they appear to be
rooted within $<$ 60 au in the disk. We confirm their global average rotation in the same sense as the disk, with a specific angular momentum $simeq$ 65 au kms. The mass-flux rate of 1.7-2.9 $times$ 10$^{-7}$M$_{odot}$ yr$^{-1}$ is 35$pm$10 times that in the atomic jet. We also detect a wider and slower outflow component surrounding this inner conical flow, which also rotates in the same direction as the disk. Our ALMA observations therefore demonstrate that the inner cone walls, and the associated scattered light cavity, do not trace the interface with infalling material, which is shown to be confined to much wider angles ($> 70^{circ}$). The properties of the conical walls are
suggestive of the interaction between an episodic inner jet or wind with an
outer disk wind, or of a massive disk wind originating from 2-5 au. However,
further modeling is required to establish their origin. In either case, such
massive outflow may significantly affect the disk structure and evolution.

We present Atacama Large Millimeter Array (ALMA) Band 6 observations at 14-20
au spatial resolution of the disk and CO(2-1) outflow around the Class I
protostar DG Tau B in Taurus. The disk is very large, both in dust continuum
(R$_{rm eff,95%}$=174 au) and CO (R$_{CO}$=700 au). It shows Keplerian
rotation around a 1.1$pm$0.2 M$_{odot}$ central star and two dust emission
bumps at $r$ = 62 and 135 au. These results confirm that large structured disks
can form at an early stage where residual infall is still ongoing. The
redshifted CO outflow at high velocity shows a striking hollow cone morphology
out to 3000 au with a shear-like velocity structure within the cone walls.
These walls coincide with the scattered light cavity, and they appear to be
rooted within $<$ 60 au in the disk. We confirm their global average rotation
in the same sense as the disk, with a specific angular momentum $simeq$ 65 au
kms. The mass-flux rate of 1.7-2.9 $times$ 10$^{-7}$M$_{odot}$ yr$^{-1}$ is
35$pm$10 times that in the atomic jet. We also detect a wider and slower
outflow component surrounding this inner conical flow, which also rotates in
the same direction as the disk. Our ALMA observations therefore demonstrate
that the inner cone walls, and the associated scattered light cavity, do not
trace the interface with infalling material, which is shown to be confined to
much wider angles ($> 70^{circ}$). The properties of the conical walls are
suggestive of the interaction between an episodic inner jet or wind with an
outer disk wind, or of a massive disk wind originating from 2-5 au. However,
further modeling is required to establish their origin. In either case, such
massive outflow may significantly affect the disk structure and evolution.

http://arxiv.org/icons/sfx.gif