Molecules with ALMA at Planet-forming Scales (MAPS). XVIII. Kinematic Substructures in the Disks of HD 163296 and MWC 480

Abstract

We explore the dynamical structure of the protoplanetary disks surrounding HD 163296 and MWC 480 as part of the Molecules with ALMA at Planet-forming Scales (MAPS) large program. Using the J = 2-1 transitions of 12 CO, 13 CO, and C 18 O imaged at spatial resolutions of ∼0 15 and with a channel spacing of 200 m s −1 , we find perturbations from Keplerian rotation in the projected velocity fields of both disks (5% of the local Keplerian velocity), suggestive of large-scale (tens of astronomical units in size), coherent flows. By accounting for the azimuthal dependence on the projection of the velocity field, the velocity fields were decomposed into azimuthally averaged orthogonal components, v f , v r , and v z . Using the optically thick 12 CO emission as a probe of the gas temperature, local variations of ≈3 K (≈5% relative changes) were observed and found to be associated with the kinematic substructures. The MWC 480 disk hosts a suite of tightly wound spiral arms. The spirals arms, in conjunction with the highly localized perturbations in the gas velocity structure (kinematic planetary signatures), indicate a giant planet, ∼1 M Jup , at a radius of ≈245 au. In the disk of HD 163296, the kinematic substructures were consistent with previous studies of Pinte et al. and Teague et al. advocating for multiple ∼1 M Jup planets embedded in the disk. These results demonstrate that molecular line observations that characterize the dynamical structure of disks can be used to search for the signatures of embedded planets. This paper is part of the MAPS special issue of the Astrophysical Journal Supplement.

Formation of Dust Rings and Gaps in Non-ideal MHD Disks Through Meridional Gas Flows

“…(3) The flow pattern in our simulation provides an attractive explanation for the meridional flows recently inferred in HD 163296 and other disks (e.g., Teague et al 2021). In particular, we found several "collapsing" regions in our fiducial simulation where the gas near the disk surface converges towards the midplane (see Fig.…”

“…One of the most exciting recent advances in protoplanetary disk research is the detection of meridional motions from ALMA molecular line observations. In the best studied case, HD 163296, Teague et al (2021) inferred the presence of meridional flows with speeds of tens of m/s (see their Fig. 5 and also Teague et al 2019).…”

The evolution of protoplanetary discs in star formation and feedback simulations

“…External photoevaporation may also take place in extremely weak UV environments for very extended discs, where only modest heating is required to unbind material. This is a possible explanation for the break in the surface density profile of IM Lup (Panić et al 2009;Cleeves et al 2016;Haworth et al 2017) and may also explain the kinematics at the CO surface of HD 163296 Teague et al (2019Teague et al ( , 2021.…”

An APEX search for carbon emission from NGC 1977 proplyds

“…Haworth et al (2017) also suggest that the outer halo of the large disc IM Lup (Panić et al 2009;Cleeves et al 2018) could also be due to a slow external wind in a < 10 G 0 environment (this is an exception because the disc is so extended that it is only very weakly gravitationally bound to the star). HD163296 also shows evidence for an outer wind at around 400 au in a weak (≤ 10 G 0 ) environment (Teague et al 2019(Teague et al , 2021 When a disc is strongly irradiated, mass is lost over a significant fraction of its surface. Since the irradiation is directional (approximately a planar field) this results in a cometary morphology which is referred to as a proplyd (see Figure 1 for a cartoon and Henney & O'Dell 1999; Kim et al 2016;Haworth et al 2021, for examples).…”