The Disk Substructures at High Angular Resolution Project (DSHARP): III. Spiral Structures in the Millimeter Continuum of the Elias 27, IM Lup, and WaOph 6 Disks. (arXiv:1812.04193v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Huang_J/0/1/0/all/0/1">Jane Huang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Andrews_S/0/1/0/all/0/1">Sean M. Andrews</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perez_L/0/1/0/all/0/1">Laura M. Pérez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhu_Z/0/1/0/all/0/1">Zhaohuan Zhu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dullemond_C/0/1/0/all/0/1">Cornelis P. Dullemond</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Isella_A/0/1/0/all/0/1">Andrea Isella</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Benisty_M/0/1/0/all/0/1">Myriam Benisty</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bai_X/0/1/0/all/0/1">Xue-Ning Bai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Birnstiel_T/0/1/0/all/0/1">Tilman Birnstiel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carpenter_J/0/1/0/all/0/1">John M. Carpenter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guzman_V/0/1/0/all/0/1">Viviana V. Guzmán</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hughes_A/0/1/0/all/0/1">A. Meredith Hughes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Oberg_K/0/1/0/all/0/1">Karin I. Öberg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ricci_L/0/1/0/all/0/1">Luca Ricci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wilner_D/0/1/0/all/0/1">David J. Wilner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_S/0/1/0/all/0/1">Shangjia Zhang</a>
We present an analysis of ALMA 1.25 millimeter continuum observations of
spiral structures in three protoplanetary disks from the Disk Substructures at
High Angular Resolution Project (Andrews et al. 2018). The disks around Elias
27, IM Lup, and WaOph 6 were observed at a resolution of $sim40-60$ mas
($sim6-7$ au). All three disks feature $m=2$ spiral patterns in conjunction
with annular substructures. Gas kinematics established by $^{12}$CO $J=2-1$
observations indicate that the continuum spiral arms are trailing. The
arm-interarm intensity contrasts are modest, typically less than 3. The Elias
27 spiral pattern extends throughout much of the disk, and the arms intersect
the gap at $Rsim69$ au. The spiral pattern in the IM Lup disk is particularly
complex-it extends about halfway radially through the disk, exhibiting pitch
angle variations with radius and interarm features that may be part of ring
substructures or spiral arm branches. Spiral arms also extend most of the way
through the WaOph 6 disk, but the source overall is much more compact than the
other two disks. We discuss possible origins for the spiral structures,
including gravitational instability and density waves induced by a stellar or
planetary companion. Unlike the millimeter continuum counterparts of many of
the disks with spiral arms detected in scattered light, these three sources do
not feature high-contrast crescent-like asymmetries or large ($R>20$ au)
emission cavities. This difference may point to multiple spiral formation
mechanisms operating in disks.
We present an analysis of ALMA 1.25 millimeter continuum observations of
spiral structures in three protoplanetary disks from the Disk Substructures at
High Angular Resolution Project (Andrews et al. 2018). The disks around Elias
27, IM Lup, and WaOph 6 were observed at a resolution of $sim40-60$ mas
($sim6-7$ au). All three disks feature $m=2$ spiral patterns in conjunction
with annular substructures. Gas kinematics established by $^{12}$CO $J=2-1$
observations indicate that the continuum spiral arms are trailing. The
arm-interarm intensity contrasts are modest, typically less than 3. The Elias
27 spiral pattern extends throughout much of the disk, and the arms intersect
the gap at $Rsim69$ au. The spiral pattern in the IM Lup disk is particularly
complex-it extends about halfway radially through the disk, exhibiting pitch
angle variations with radius and interarm features that may be part of ring
substructures or spiral arm branches. Spiral arms also extend most of the way
through the WaOph 6 disk, but the source overall is much more compact than the
other two disks. We discuss possible origins for the spiral structures,
including gravitational instability and density waves induced by a stellar or
planetary companion. Unlike the millimeter continuum counterparts of many of
the disks with spiral arms detected in scattered light, these three sources do
not feature high-contrast crescent-like asymmetries or large ($R>20$ au)
emission cavities. This difference may point to multiple spiral formation
mechanisms operating in disks.
http://arxiv.org/icons/sfx.gif
