Directly tracing the vertical stratification of molecules in protoplanetary disks

Abstract

We aim to directly trace the vertical location of the emitting surface of multiple molecular tracers in protoplanetary disks. Our sample of disks includes Elias 2-27, WaOph 6 and the sources targeted by the MAPS ALMA Large Program. The set of molecules studied include CO isotopologues in various transitions, HCN, CN, H2CO, HCO+, C2H and c-C3H2. The vertical emitting region is determined directly from the channel maps, implementing accurate masking of the channel emission to recover the vertical location of the emission surface even at large radial distances from the star and for low-SNR lines. The vertical location of the emitting layer is obtained for 4-10 lines in each disk. IM Lup, HD163296 and MWC 480 12CO and 13CO show vertical modulations, which are coincident with dust gaps and kinematical perturbations. We also present estimates of the gas pressure scale height in the disks from the MAPS sample. Compared to physical-chemical models we find good agreement with the vertical location of CO isotopologues. In HD 163296 CN and HCN trace a similar intermediate layer, for the other disks, the UV flux tracers and the vertical profiles of HCN and C2H are lower than predicted in theoretical models. HCN and H2CO show a highly structured vertical profile, possibly indicative of different formation pathways. It is possible to trace the vertical locations of multiple molecular species that trace a wide variety of physical and chemical disk properties. The distribution of CO isotopologues are found at a wide range of vertical heights $z/r=$ 0.5-0.05. Other molecular lines are mostly found at $z/r\le$0.15. The vertical layering of molecules is in agreement with theory in some systems, but not in all, therefore dedicated chemical-physical models are needed to further study and understand the emission surfaces.

arXiv commentAccepted for publication in A&A. 29 pages, 28 figures

References in corpus (64)

• A computer program for fast non-LTE analysis of interstellar line spectra
• Spectral Energy Distributions of T Tauri Stars With Passive Circumstellar Disks
• The Disk Substructures at High Angular Resolution Project (DSHARP): I. Motivation, Sample, Calibration, and Overview
• Resolved Images of Large Cavities in Protoplanetary Transition Disks
• Accretion Disks around Young Objects. I. The Detailed Vertical Structure
• The Disk Substructures at High Angular Resolution Project (DSHARP): II. Characteristics of Annular Substructures
• Consistent dust and gas models for protoplanetary disks. I. Disk shape, dust settling, opacities, and PAHs
• Disks ARound TTauri Stars with Sphere (DARTTS-S) I: Sphere / IRDIS Polarimetric Imaging of 8 prominent TTauri Disks
• Spiral Density Waves in a Young Protoplanetary Disk
• A Kinematical Detection of Two Embedded Jupiter Mass Planets in HD 163296
• Kinematic evidence for an embedded protoplanet in a circumstellar disc
• Spectral Energy Distributions of T Tauri and Herbig Ae Disks: Grain Mineralogy, Parameter Dependences, and Comparison with ISO LWS Observations
• emcee v3: A Python ensemble sampling toolkit for affine-invariant MCMC
• Molecules with ALMA at Planet-forming Scales (MAPS) I: Program Overview and Highlights
• The warm gas atmosphere of the HD 100546 disk seen by Herschel (Evidence of a gas-rich, carbon-poor atmosphere?)
• Warm Molecular Layers in Protoplanetary Disks
• Survival of molecular gas in cavities of transition disks (I. CO)
• A Spatially Resolved Vertical Temperature Gradient in the HD 163296 Disk
• Chemical Processes in Protoplanetary Disks
• Direct mapping of the temperature and velocity gradients in discs. Imaging the vertical CO snow line around IM Lupi
• Protoplanetary disk masses from CO isotopologues line emission
• Observations of edge-on protoplanetary disks with ALMA I. Results from continuum data
• Molecules with ALMA at Planet-forming Scales (MAPS) V: CO gas distributions
• 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
• Vertical structure models of T Tauri and Herbig Ae/Be disks
• Submillimeter lines from circumstellar disks around pre-main sequence stars
• The newborn planet population emerging from ring-like structures in discs
• Direct detection of scattered light gaps in the transitional disk around HD 97048 with VLT/SPHERE
• Meridional circulation of gas into gaps opened by giant planets in three-dimensional low-viscosity disks
• Determining protoplanetary disk gas masses from CO isotopologues line observations
• Axi-symmetric models of ultraviolet radiative transfer with applications to circumstellar disk chemistry
• Molecules with ALMA at Planet-forming Scales (MAPS) IV: Emission Surfaces and Vertical Distribution of Molecules
• Chemistry of a protoplanetary disk with grain settling and Lyman alpha radiation
• Gap Opening in 3D: Single Planet Gaps
• Constraining Gas-Phase Carbon, Oxygen, and Nitrogen in the IM Lup Protoplanetary Disk
• Bright C2H emission in protoplanetary disks in Lupus: high volatile C/O>1 ratios
• A break in the gas and dust surface density of the disc around the T Tauri star IM Lup
• CN rings in full protoplanetary disks around young stars as probes of disk structure
• Nitrogen isotope fractionation in protoplanetary disks
• Observability of planet-disc interactions in CO kinematics
• Spiral Arms and a Massive Dust Disk with non-Keplerian Kinematics: Possible Evidence for Gravitational Instability in the Disk of Elias 2-27
• A new planet candidate detected in a dust gap of the disc around HD 163296 through localised kinematic signatures. An observational validation of the Discminer
• Molecules with ALMA at Planet-forming Scales (MAPS) VI: Distribution of the small organics HCN, C2H, and H2CO
• Effects of the Planetary Temperature on the Circumplanetary Disk and on the Gap
• Molecules with ALMA at Planet-forming Scales (MAPS). IX. Distribution and Properties of the Large Organic Molecules HC${}_3$N, CH${}_3$CN, and $c$-C${}_3$H${}_2$
• The Disc Miner I: A statistical framework to detect and quantify kinematical perturbations driven by young planets in discs
• An ALMA Survey of H${}_2$CO in Protoplanetary Disks
• ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT) II: Vertical stratification of CO, CS, CN, H${}_2$CO, and CH${}_3$OH in a Class I disk
• The Distribution and Chemistry of H${}_2$CO in the DM Tau Protoplanetary Disk
• Scattered light shadows in warped protoplanetary discs
• A dynamical measurement of the disk mass in Elias 2-27
• Molecules with ALMA at Planet-forming Scales (MAPS) XI: CN and HCN as Tracers of Photochemistry in Disks
• Increased H${}_2$CO production in the outer disk around HD 163296
• Meridional Circulation of Dust and Gas in the Circumstellar Disk: Delivery of Solids onto the Circumplanetary Region
• Molecules with ALMA at Planet-forming Scales (MAPS) XIII: HCO${}^{+}$ and disk ionization structure
• Gas temperature structure across transition disk cavities
• ISPY -- NACO Imaging Survey for Planets around Young stars: Survey description and results from the first 2.5 years of observations
• Spiral-driven accretion in protoplanetary discs - III tri-dimensional simulations
• The TW Hya Rosetta Stone Project II: Spatially resolved emission of formaldehyde hints at low-temperature gas-phase formation
• Investigating the Relative Gas and Small Dust Grain Surface Heights in Protoplanetary Disks
• The Excitation Conditions of CN in TW Hya
• The Anatomy of an Unusual Edge-on Protoplanetary Disk. II. Gas temperature and a warm outer region
• Vertically extended and asymmetric CN emission in the Elias 2-27 protoplanetary disk
• Tracing Molecular Stratification within an Edge-on Protoplanetary Disk

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• Early Planet Formation in Embedded Disks (eDisk). II. Limited Dust Settling and Prominent Snow Surfaces in the Edge-on Class I Disk IRAS 04302+2247
• The Disc Miner II: Revealing Gas substructures and Kinematic signatures from Planet-disc interaction through line profile analysis
• exoALMA V: Gaseous Emission Surfaces and Temperature Structures
• Mapping Protoplanetary Disk Vertical Structure with CO Isotopologue Line Emission
• exoALMA. VI. Rotating under Pressure: Rotation curves, azimuthal velocity substructures, and pressure variations
• exoALMA XV: Interpreting the height of CO emission layer
• ALMA high-resolution observations unveil planet formation shaping molecular emission in the PDS 70 disk
• Radial and vertical constraints on the icy origin of H${}_2$CO in the HD 163296 Protoplanetary Disk
• A dichotomy in group II Herbig disks: ALMA gas disk height measurements show both shadowed large vertically extended disks and compact flat disks
• A young gas giant and hidden substructures in a protoplanetary disk
• An SMA Survey of Chemistry in Disks around Herbig AeBe Stars
• Vertical CO surfaces as a probe for protoplanetary disk mass and carbon depletion
• Vertical and radial distribution of atomic carbon in HD 163296
• Constraints on the gas-phase C/O ratio of DR Tau's outer disk from CS, SO, and C${}_2$H observations
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• exoALMA XXI: The Morphology and Dynamics of Vertical Flows
• Edge-On Disk Study (EODS) III: Molecular Stratification in the Flying Saucer Disk
• Gravito-turbulent bi-fluid protoplanetary discs: 1. An analytical perspective to stratification
• New methods for ALMA angular-scale based observation scheduling, quality assessment, and beam shaping II: refinements
• Self-gravity in thin protoplanetary discs: 1. The smoothing-length approximation versus the exact self-gravity kernel