Chemistry in Disks. IX. Observations and modeling of HCO+ and DCO+ in DM Tau

Abstract

We present resolved Plateau de Bure Array observations of DM Tau in lines of HCO+ (3-2), (1-0) and DCO+ (3-2). A power-law fitting approach allowed a derivation of column densities of these two molecules. A chemical inner hole of ~50 AU was found in both HCO+ and DCO+ with DCO+ emission extending to only 450 AU. An isotopic ratio of R_D = N(DCO+) / N(HCO+) was found to range from 0.1 at 50 AU and 0.2 at 450 AU. Chemical modeling allowed an exploration of the sensitivity of these molecular abundances to physical parameters out with temperature, finding that X-rays were the domination ionization source in the HCO+ molecular region and that R_D also is sensitive to the CO depletion. The ionization fraction, assuming a steady state system, was found to be x(e-) ~ 10${}^{-7}$. Modeling suggests that HCO+ is the dominant charged molecule in the disk but its contribution to ionization fraction is dwarfed by atmoic ions such as C+, S+ and H+.

arXiv comment13 pages with 8 figures, to be published in A&A, accepted 29/12/14

References in corpus (80)

• Spectral Energy Distributions of T Tauri Stars With Passive Circumstellar Disks
• Protoplanetary Disks and Their Evolution
• Cold Dark Clouds: The Initial Conditions for Star Formation
• Formation of methyl formate and other organic species in the warm-up phase of hot molecular cores
• Structure of Stationary Photodissociation Fronts
• A Major Asymmetric Dust Trap in a Transition Disk
• A KInetic Database for Astrochemistry (KIDA)
• Formation rates of complex organics in UV irradiated CH3OH-rich ices I: Experiments
• Our astrochemical heritage
• Accretion Disks Around Young Objects. II. Tests of Well-Mixed Models with Ism Dust
• Non-thermal desorption from interstellar dust grains via exothermic surface reactions
• Dynamical Masses of T Tauri Stars and Calibration of PMS Evolution
• Molecular ions in L1544. II. The ionization degree
• Monte Carlo radiative transfer in protoplanetary disks
• Radiation thermo-chemical models of protoplanetary disks I. Hydrostatic disk structure and inner rim
• An Old Disk That Can Still Form a Planetary System
• Imaging of the CO Snow Line in a Solar Nebula Analog
• Molecular Hydrogen Formation on Astrophysically Relevant Surfaces
• Probing the structure of protoplanetary disks: a comparative study of DM Tau, LkCa 15 and MWC 480
• Chemistry of Dark Clouds: Databases, Networks, and Models
• Photodesorption of ices I: CO, N2 and CO2
• An Earth-sized Planet in the Habitable Zone of a Cool Star
• Reactive Desorption and Radiative Association as Possible Drivers of Complex Molecule Formation in the Cold Interstellar Medium
• Spiral Arms in the Asymmetrically Illuminated Disk of MWC 758 and Constraints on Giant Planets
• Photoprocesses in protoplanetary disks
• Complete Depletion in prestellar cores
• Warm Molecular Layers in Protoplanetary Disks
• Chemistry in Disks. IV. Benchmarking gas-grain chemical models with surface reactions
• A Spatially Resolved Vertical Temperature Gradient in the HD 163296 Disk
• Exclusion of Cosmic Rays in Protoplanetary Disks: Stellar and Magnetic Effects
• Chemical Processes in Protoplanetary Disks
• Master Equation for Hydrogen Recombination on Grain Surfaces
• Chemical evolution of turbulent protoplanetary disks and the Solar nebula
• Chemical modeling of L183 (= L134N) : an estimate of the ortho/para H2 ratio
• The importance of the ortho:para H2 ratio for the deuteration of molecules during pre-protostellar collapse
• CO ice photodesorption: A wavelength-dependent study
• Disk Imaging Survey of Chemistry with SMA: II. Southern Sky Protoplanetary Disk Data and Full Sample Statistics
• The Effects of UV Continuum and Lyman alpha Radiation on the Chemical Equilibrium of T Tauri Disks
• Survey of ortho-H2D+(1_{1,0}-1_{1,1}) in dense cloud cores
• Disk Imaging Survey of Chemistry with SMA (DISCS): I. Taurus Protoplanetary Disk Data
• Interstellar deuterated ammonia: From NH3 to ND3
• Numerical methods for non-LTE line radiative transfer: Performance and convergence characteristics
• Reduction of chemical networks. II. Analysis of the fractional ionisation in protoplanetary discs
• Resolving the chemistry in the disk of TW Hydrae I. Deuterated species
• DIGIT survey of far-infrared lines from protoplanetary disks I
• 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
• Chemistry in disks I - Deep search for N${}_2$H${}^{+}$ in the protoplanetary disks around LkCa 15, MWC 480, and DM Tau
• New extended deuterium fractionation model: assessment at dense ISM conditions and sensitivity analysis
• Exclusion of Cosmic Rays in Protoplanetary Disks. II. Chemical Gradients and Observational Signatures
• Chemo-dynamical deuterium fractionation in the early solar nebula: The origin of water on Earth and in asteroids and comets
• The Distribution of Ortho-H_2D+(1_1,0 - 1_1,1) in L1544: Tracing the Deuteration Factory in Prestellar Cores
• Wavelength-dependent UV photodesorption of pure N2 and O2 ices
• Chemistry in Disks. III. -- Photochemistry and X-ray driven chemistry probed by the ethynyl radical (CCH) in DM Tau, LkCa 15, and MWC 480
• Protoplanetary Disk Structure With Grain Evolution: the ANDES Model
• Fast Radial Flows in Transition Disk Holes
• Chemistry in Disks VIII: the CS molecule as an analytic tracer of turbulence in disks
• Turbulence in weakly-ionized proto-planetary disks
• Herschel-PACS observation of the 10 Myr old T Tauri disk TW Hya: Constraining the disk gas mass
• Water depletion in the disk atmosphere of Herbig AeBe stars
• CID: Chemistry in disks VI.sulfur-bearing molecules in the protoplanetary disks surrounding LkCa15, MWC480, DM Tau, and GO Tau
• Deuterated molecules as a probe of ionization fraction in dense interstellar clouds
• On the Ortho:Para Ratio of H3+ in Diffuse Molecular Clouds
• Detection of DCO+ in a circumstellar disk
• HD depletion in starless cores
• Cosmic ray induced ionisation of a molecular cloud shocked by the W28 supernova remnant
• Deuterated molecules in DM Tau: DCO+, but no HDO
• Radionuclide Ionization in Protoplanetary Disks: Calculations of Decay Product Radiative Transfer
• Molecular line radiative transfer in protoplanetary disks: Monte Carlo simulations versus approximate methods
• Extended emission of D2H+ in a prestellar core
• The 69 micron forsterite band in spectra of protoplanetary disks - Results from the Herschel DIGIT programme
• Evidence for Multiple Pathways to Deuterium Enhancements in Protoplanetary Disks
• The Ionization Fraction in the DM Tau Protoplanetary Disk
• Direct Measurement of Interstellar Extinction Toward Young Stars Using Atomic Hydrogen Lyman-$\alpha$ Absorption
• Chemistry in Disks. II. -- Poor molecular content of the AB Aur disk
• First Time-dependent Study of H2 and H3+ Ortho-Para Chemistry in the Diffuse Interstellar Medium: Observations Meet Theoretical Predictions
• Detection of H2D+ in a massive prestellar core in Orion B
• A deep search for H2D+ in protoplanetary disks
• Probable detection of H2D+ in the starless core Barnard 68
• H${}_2$D${}^{+}$ line emission in Proto-Planetary Disks

Cited by in corpus (46)

• Our astrochemical heritage
• The Disk Substructures at High Angular Resolution Project (DSHARP): II. Characteristics of Annular Substructures
• Molecules with ALMA at Planet-forming Scales (MAPS) I: Program Overview and Highlights
• A Three-Dimensional View of Turbulence: Constraints on Turbulent Motions in the HD 163296 Protoplanetary Disk using DCO${}^{+}$
• The cometary composition of a protoplanetary disk as revealed by complex cyanides
• Three radial gaps in the disk of TW Hydrae imaged with SPHERE
• Mass measurements in protoplanetary disks from hydrogen deuteride
• Measuring turbulent motion in planet-forming disks with ALMA: A detection around DM Tau and non-detections around MWC 480 and V4046 Sgr
• Disk Imaging Survey of Chemistry with SMA (DISCS): I. Taurus Protoplanetary Disk Data
• Accretion kinematics through the warped transition disk in HD142527 from resolved CO(6-5) observations
• Sulfur chemistry in protoplanetary disks: CS and H2CS
• An ALMA survey of DCN/H${}^{13}$CN and DCO${}^{+}$/H${}^{13}$CO${}^{+}$ in protoplanetary disks
• Rotating molecular outflows: the young T Tauri star in CB26
• Elemental nitrogen partitioning in dense interstellar clouds
• Consistent dust and gas models for protoplanetary disks III. Models for selected objects from the FP7 DIANA project
• Double DCO+ rings reveal CO ice desorption in the outer disk around IM Lup
• Chemistry in disks. XI. Sulfur-bearing species as tracers of protoplanetary disk physics and chemistry: the DM Tau case
• Chemistry in Disks X: The Molecular Content of Proto-planetary Disks in Taurus
• Chemical Modelling of Young Stellar Objects, I. Method and Benchmarks
• The Distribution and Chemistry of H${}_2$CO in the DM Tau Protoplanetary Disk
• Stellar energetic particle ionization in protoplanetary disks around T Tauri stars
• DCO${}^{+}$, DCN and N${}_2$D${}^{+}$ reveal three different deuteration regimes in the disk around the Herbig Ae star HD163296
• The chemistry of disks around T Tauri and Herbig Ae/Be stars
• An evolutionary study of volatile chemistry in protoplanetary disks
• Chemically tracing the water snowline in protoplanetary disks with HCO${}^{+}$
• H2CO distribution and formation in the TW Hya disk
• Molecules with ALMA at Planet-forming Scales (MAPS) XIII: HCO${}^{+}$ and disk ionization structure
• Probing midplane CO abundance and gas temperature with DCO${}^{+}$ in the protoplanetary disk around HD 169142
• Evidence for DCO+ as a probe of ionization in the warm disk surface
• X-ray radiative transfer in protoplanetary disks - The role of dust and X-ray background fields
• Multiple paths of deuterium fractionation in protoplanetary disks
• Resolved molecular line observations reveal an inherited molecular layer in the young disk around TMC1A
• The TW Hya Rosetta Stone Project I: Radial and vertical distributions of DCN and DCO+
• Detection of HC18O+ in a protoplanetary disk: exploring oxygen isotope fractionation of CO
• Chemical signatures of a warped protoplanetary disc
• Detection of N${}_2$D${}^{+}$ in a protoplanetary disk
• Protoplanetary disks: Sensitivity of the chemical composition to various model parameters
• Thermochemical modelling of brown dwarf discs
• First detections of H13CO+ and HC15N in the disk around HD 97048: Evidence for a cold gas reservoir in the outer disk
• The evolution of HCO${}^{+}$ in molecular clouds using a novel chemical post-processing algorithm
• Using HCO${}^{+}$ isotopologues as tracers of gas depletion in protoplanetary disk gaps
• 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
• PRODIGE -- Planet-forming disks in Taurus with NOEMA. I. Overview and first results for 12CO, 13CO, and C18O
• The gas disk: Evolution and chemistry
• Protoplanetary Disk Chemistry