DCO${}^{+}$, DCN and N${}_2$D${}^{+}$ reveal three different deuteration regimes in the disk around the Herbig Ae star HD163296

Abstract

The formation pathways of deuterated species trace different regions of protoplanetary disks and may shed light into their physical structure. We aim to constrain the radial extent of main deuterated species; we are particularly interested in spatially characterizing the high and low temperature pathways for enhancing deuteration of these species. We observed the disk surrounding the Herbig Ae star HD 163296 using ALMA in Band 6 and obtained resolved spectral imaging data of DCO${}^{+}$ ($J$=3-2), DCN ($J$=3-2) and N${}_2$D${}^{+}$ ($J$=3-2). We model the radial emission profiles of DCO${}^{+}$, DCN and N${}_2$D${}^{+}$, assuming their emission is optically thin, using a parametric model of their abundances and radial excitation temperature estimates. DCO${}^{+}$ can be described by a three-region model, with constant-abundance rings centered at 70 AU, 150 AU and 260 AU. The DCN radial profile peaks at about ~60 AU and N${}_2$D${}^{+}$ is seen in a ring at ~160 AU. Simple models of both molecules using constant abundances reproduce the data. Assuming reasonable average excitation temperatures for the whole disk, their disk-averaged column densities (and deuterium fractionation ratios) are 1.6-2.6$\times 10^{12}$ cm${}^{-2}$ (0.04-0.07), 2.9-5.2$\times 10^{12}$ cm${}^{-2}$ ($\sim$0.02) and 1.6-2.5 $\times 10^{11}$ cm${}^{-2}$ (0.34-0.45) for DCO${}^{+}$, DCN and N${}_2$D${}^{+}$, respectively. Our simple best-fit models show a correlation between the radial location of the first two rings in DCO${}^{+}$ and the DCN and N${}_2$D${}^{+}$ abundance distributions that can be interpreted as the high and low temperature deuteration pathways regimes. The origin of the third DCO${}^{+}$ ring at 260 AU is unknown but may be due to a local decrease of ultraviolet opacity allowing the photodesorption of CO or due to thermal desorption of CO as a consequence of radial drift and settlement of dust grains.

References in corpus (37)

• An atomic and molecular database for analysis of submillimetre line observations
• The Spitzer ice legacy: Ice evolution from cores to protostars
• Flaring vs. self-shadowed disks: the SEDs of Herbig Ae/Be stars
• Probing the evolutionary status of starless cores through N2H+ and N2D+ observations
• Molecular ions in L1544. II. The ionization degree
• Imaging of the CO Snow Line in a Solar Nebula Analog
• Does IRAS 16293-2422 have a hot core? Chemical inventory and abundance changes in its protostellar environment
• Simulation of the Formation and Morphology of Ice Mantles on Interstellar Grains
• LIME - a flexible, non-LTE line excitation and radiation transfer method for millimeter and far-infrared wavelengths
• Complete Depletion in prestellar cores
• On the internal structure of starless cores. II. A molecular survey of L1498 and L1517B
• Different dust and gas radial extents in protoplanetary disks: consistent models of grain growth and CO emission
• Disk Imaging Survey of Chemistry with SMA (DISCS): I. Taurus Protoplanetary Disk Data
• Chemical Imaging of the CO Snow Line in the HD 163296 Disk
• Mass inventory of the giant-planet formation zone in a solar nebula analog
• Resolving the chemistry in the disk of TW Hydrae I. Deuterated species
• Carbon isotope fractionation in protoplanetary disks
• Resolving the CO Snow Line in the Disk around HD 163296
• ALMA imaging of the CO snowline of the HD 163296 disk with DCO+
• The chemistry of multiply deuterated molecules in protoplanetary disks. I. The outer disk
• Robustness of N2H+ as tracer of the CO snowline
• On the Commonality of 10-30AU Sized Axisymmetric Dust Structures in Protoplanetary Disks
• New extended deuterium fractionation model: assessment at dense ISM conditions and sensitivity analysis
• An ALMA survey of DCN/H${}^{13}$CN and DCO${}^{+}$/H${}^{13}$CO${}^{+}$ in protoplanetary disks
• Double DCO+ rings reveal CO ice desorption in the outer disk around IM Lup
• The HD 163296 Circumstellar Disk in Scattered Light: Evidence of Time-Variable Self-Shadowing
• Chemistry in Disks. IX. Observations and modeling of HCO+ and DCO+ in DM Tau
• Multiple Carbon monoxide Snow-lines in Disks Sculpted by Radial Drift
• Detection of DCO+ in a circumstellar disk
• Shadows and cavities in protoplanetary disks: HD163296, HD141569A, and HD150193A in polarized light
• Deuterated molecules in DM Tau: DCO+, but no HDO
• Stacking Spectra in Protoplanetary Disks: Detecting Intensity Profiles from Hidden Molecular Lines in HD 163296
• Chemical evolution in the early phases of massive star formation II: Deuteration
• Evidence for Multiple Pathways to Deuterium Enhancements in Protoplanetary Disks
• A low-mass protostar's disk-envelope interface: disk-shadowing evidence from ALMA DCO+ observations of VLA1623
• Evidence for DCO+ as a probe of ionization in the warm disk surface
• Detection of N${}_2$D${}^{+}$ in a protoplanetary disk

Cited by in corpus (48)

• ALMA Survey of Lupus Protoplanetary Disks II: Gas Disk Radii
• Molecules with ALMA at Planet-forming Scales (MAPS) I: Program Overview and Highlights
• First Detection of the Simplest Organic Acid in a Protoplanetary Disk
• Sulfur chemistry in protoplanetary disks: CS and H2CS
• A survey of C2H, HCN, and C18O in protoplanetary disks
• A multi-frequency ALMA characterization of substructures in the GM Aur protoplanetary disk
• Methanol and its relation to the water snowline in the disk around the young outbursting star V883 Ori
• HL Tau disk in HCO+ (3-2) and (1-0) with ALMA: gas density, temperature, gap, and one-arm spiral
• Molecules with ALMA at Planet-forming Scales (MAPS) VI: Distribution of the small organics HCN, C2H, and H2CO
• Gas Disk Sizes from CO Line Observations: A Test of Angular Momentum Evolution
• Unveiling the physical conditions of the youngest disks: A warm embedded disk in L1527
• An ALMA Survey of H${}_2$CO in Protoplanetary Disks
• The chemical inventory of the planet-hosting disk PDS 70
• Upper limits on CH${}_3$OH in the HD 163296 protoplanetary disk: evidence for a low gas-phase CH${}_3$OH/H${}_2$CO ratio
• High-contrast imaging of HD 163296 with the Keck/NIRC2 L'-band vortex coronograph
• Sulphur monoxide emission tracing an embedded planet in the HD 100546 protoplanetary disk
• Tracing the cold and warm physico-chemical structure of deeply embedded protostars: IRAS 16293-2422 versus VLA 1623-2417
• Probing midplane CO abundance and gas temperature with DCO${}^{+}$ in the protoplanetary disk around HD 169142
• The ALMA Survey of 70 $\mu$m Dark High-mass Clumps in Early Stages (ASHES). IV. Star formation signatures in G023.477
• Interpreting high spatial resolution line observations of planet-forming disks with gaps and rings -- The case of HD 163296
• Large-scale CO spiral arms and complex kinematics associated with the T Tauri star RU Lup
• The ALMA Lupus protoplanetary disk survey: evidence for compact gas disks and molecular rings from CN
• Multiple paths of deuterium fractionation in protoplanetary disks
• Dust continuum emission and the upper limit fluxes of sub-millimeter water lines of the protoplanetary disk around HD 163296 observed by ALMA
• Dynamical stellar masses of pre-main sequence stars in Lupus and Taurus obtained with ALMA surveys in comparison with stellar evolutionary models
• The TW Hya Rosetta Stone Project II: Spatially resolved emission of formaldehyde hints at low-temperature gas-phase formation
• Molecules with ALMA at Planet-forming Scales (MAPS). X. Studying deuteration at high angular resolution toward protoplanetary disks
• The ALMA view of MP Mus (PDS 66): a protoplanetary disk with no visible gaps down to 4 au scales
• Mass Assembly of Stellar Systems and their Evolution with the SMA (MASSES) -- Full Data Release
• Stellar masses and disk properties of Lupus young stellar objects traced by velocity-aligned stacked ALMA 13CO and C18O spectra
• Investigating the asymmetric chemistry in the disk around the young star HD 142527
• The TW Hya Rosetta Stone Project I: Radial and vertical distributions of DCN and DCO+
• An ALMA Survey of Chemistry in Disks around M4-M5 Stars
• Investigating the gas-to-dust ratio in the protoplanetary disk of HD 142527
• A 3mm chemical exploration of small organics in Class I YSOs
• ALMA ACA and Nobeyama observations of two Orion cores in deuterated molecular lines
• Radial and vertical constraints on the icy origin of H${}_2$CO in the HD 163296 Protoplanetary Disk
• First detections of H13CO+ and HC15N in the disk around HD 97048: Evidence for a cold gas reservoir in the outer disk
• APEX observations of ortho-H${}_2$D${}^{+}$ towards dense cores in the Orion B9 filament
• Exploring DCO${}^{+}$ as a tracer of thermal inversion in the disk around the Herbig Ae star HD163296
• Cold Deuterium Fractionation in the Nearest Planet-Forming Disk
• Evidence for a Sharp CO Snowline Transition in a Protoplanetary Disk and Implications for Millimeter-wave Observations of CO Isotopologues
• Revealing a Centrally Condensed Structure in OMC-3/MMS 3 with ALMA High Resolution Observations
• Molecular deuterations in massive Starless Clump Candidates
• Molecules with ALMA at Planet-forming Scales (MAPS) III: Characteristics of Radial Chemical Substructures
• Gas-phase Elemental abundances in Molecular cloudS (GEMS) XI. The evolution of HCN, HNC, and N2H+ isotopic ratios in starless cores
• Singly- and doubly-deuterated formaldehyde in massive star-forming regions
• Protoplanetary Disk Chemistry