Constraints on the gas-phase C/O ratio of DR Tau's outer disk from CS, SO, and C${}_2$H observations

Abstract

Millimeter wavelength observations of Class II protoplanetary disks often display strong emission from hydrocarbons and high CS/SO values, providing evidence that the gas-phase C/O ratio commonly exceeds 1 in their outer regions. We present new NOEMA observations of CS $5-4$, SO $7_6-6_5$ and $5_6-4_5$, C${}_2$H $N=3-2$, HCN $3-2$, HCO${}^{+}$ $3-2$, and H${}^{13}$CO${}^{+}$ $3-2$ in the DR Tau protoplanetary disk at a resolution of $\sim 0.4^{\prime \prime }$ (80 au). Estimates for the disk-averaged CS/SO ratio range from $\sim 0.4-0.5$, the lowest value reported thus far for a T Tauri disk. At a projected separation of $\sim 180$ au northeast of the star, the SO moment maps exhibit a clump that has no counterpart in the other lines, and the CS/SO value decreases to $<0.2$ at its location. Thermochemical models calculated with DALI indicate that DR Tau's low CS/SO ratio and faint C${}_2$H emission can be explained by a gas-phase C/O ratio that is $<1$ at the disk radii traced by NOEMA. Comparisons of DR Tau's SO emission to maps of extended structures traced by ${}^{13}$CO suggest that late infall may contribute to driving down the gas-phase C/O ratio of its disk.

arXiv commentPublished in ApJ

References in corpus (97)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Astropy: A Community Python Package for Astronomy
• The chemical composition of the Sun
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• scikit-image: Image processing in Python
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• The Disk Substructures at High Angular Resolution Project (DSHARP): I. Motivation, Sample, Calibration, and Overview
• CASA, the Common Astronomy Software Applications for Radio Astronomy
• The effects of snowlines on C/O in planetary atmospheres
• The UMIST database for astrochemistry 2012
• Protoplanetary Disk Structures in Ophiuchus
• A KInetic Database for Astrochemistry (KIDA)
• Gaps and Rings in an ALMA Survey of Disks in the Taurus Star-forming Region
• Multi-Scale CLEAN deconvolution of radio synthesis images
• C/O ratio as a Dimension for Characterizing Exoplanetary Atmospheres
• Dust and Gas in the disc of HL Tauri: Surface density, dust settling, and dust-to-gas ratio
• Effects of Dust Growth and Settling in T Tauri Disks
• Consistent dust and gas models for protoplanetary disks. I. Disk shape, dust settling, opacities, and PAHs
• Modeling optical properties of cosmic dust grains using a distribution of hollow spheres
• CMasher: Scientific colormaps for making accessible, informative and 'cmashing' plots
• The warm gas atmosphere of the HD 100546 disk seen by Herschel (Evidence of a gas-rich, carbon-poor atmosphere?)
• Compact Disks in a High Resolution ALMA Survey of Dust Structures in the Taurus Molecular Cloud
• Survival of molecular gas in cavities of transition disks (I. CO)
• On the reservoir of sulphur in dark clouds : chemistry and elemental abundance reconciled
• Volatile carbon locking and release in protoplanetary disks. A study of TW Hya and HD 100546
• Lupus disks with faint CO isotopologues: low gas/dust or large carbon depletion?
• Protoplanetary disk masses from CO isotopologues line emission
• A Significantly Low CO Abundance Toward the TW Hya Protoplanetary Disk: A Path to Active Carbon Chemistry?
• Modeling Sulfur Depletion in Interstellar Clouds
• Hydrocarbon emission rings in protoplanetary disks induced by dust evolution
• Observations of edge-on protoplanetary disks with ALMA I. Results from continuum data
• Gas and Dust Emission at the Outer Edge of Protoplanetary Disks
• Different dust and gas radial extents in protoplanetary disks: consistent models of grain growth and CO emission
• An interferometric study of the low-mass protostar IRAS 16293-2422: small scale organic chemistry
• Determining protoplanetary disk gas masses from CO isotopologues line observations
• Molecules with ALMA at Planet-forming Scales (MAPS) IV: Emission Surfaces and Vertical Distribution of Molecules
• Abundant refractory sulfur in protoplanetary disks
• Sensitivity analysis of grain surface chemistry to binding energies of ice species
• Physical and Chemical Structure of Protoplanetary Disks with Grain Growth
• Formation of Water in the Warm Atmospheres of Protoplanetary Disks
• ALMA imaging of the CO snowline of the HD 163296 disk with DCO+
• Sulfur chemistry in protoplanetary disks: CS and H2CS
• A sensitive survey for 13CO, CN, H2CO and SO in the disks of T Tauri and Herbig Ae stars
• Detecting Weak Spectral Lines in Interferometric Data through Matched Filtering
• Systematic Variations of CO Gas Abundance with Radius in Gas-rich Protoplanetary Disks
• ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT) VI: Accretion shocks in the disk of DG Tau and HL Tau
• Characterizing the IYJ Excess Continuum Emission in T Tauri Stars
• A survey of C2H, HCN, and C18O in protoplanetary disks
• 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
• An ALMA survey of DCN/H${}^{13}$CN and DCO${}^{+}$/H${}^{13}$CO${}^{+}$ in protoplanetary disks
• A multi-frequency ALMA characterization of substructures in the GM Aur protoplanetary disk
• Frankenstein: Protoplanetary disc brightness profile reconstruction at sub-beam resolution with a rapid Gaussian process
• 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
• CID: Chemistry in disks VI.sulfur-bearing molecules in the protoplanetary disks surrounding LkCa15, MWC480, DM Tau, and GO Tau
• Multiple Carbon monoxide Snow-lines in Disks Sculpted by Radial Drift
• Rapid Evolution of Volatile CO from the Protostellar Disk Stage to the Protoplanetary Disk Stage
• Molecules with ALMA at Planet-forming Scales (MAPS) VI: Distribution of the small organics HCN, C2H, and H2CO
• The Flying Saucer: Tomography of the thermal and density gas structure of an edge-on protoplanetary disk
• CCH in prestellar cores
• The chemical inventory of the planet-hosting disk PDS 70
• Deep exploration of the planets HR 8799 b, c, and d with moderate resolution spectroscopy
• The TW Hya Rosetta Stone Project III: Resolving the Gaseous Thermal Profile of the Disk
• Directly tracing the vertical stratification of molecules in protoplanetary disks
• Hyperfine Structure in H^{13}CO^{+} and ^{13}CO: measurement, analysis, and consequences for the study of dark clouds
• 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
• Assessing the C/O Ratio Formation Diagnostic: A Potential Trend with Companion Mass
• An unbiased ALMA spectral survey of the LkCa 15 and MWC 480 protoplanetary disks
• Modeling accretion shocks at the disk-envelope interface -- Sulfur chemistry
• An evolutionary study of volatile chemistry in protoplanetary disks
• Sulphur monoxide exposes a potential molecular disk wind from the planet-hosting disk around HD100546
• Carbon depletion observed inside T Tauri inner rims: Formation of icy, kilometer size planetesimals by 1 Myr
• Sulphur monoxide emission tracing an embedded planet in the HD 100546 protoplanetary disk
• High spatial resolution imaging of SO and H2CO in AB Auriga: the first SO image in a transitional disk
• Gas temperature structure across transition disk cavities
• Tracing snowlines and C/O ratio in a planet-hosting disk: ALMA molecular line observations towards the HD169142 disk
• SO and SiS Emission Tracing an Embedded Planet and Compact ${}^{12}$CO and ${}^{13}$CO Counterparts in the HD 169142 Disk
• Early Planet Formation in Embedded Disks (eDisk). IV. The Ringed and Warped Structure of the Disk around the Class I Protostar L1489 IRS
• Modest dust settling in the IRAS04302+2247 Class I protoplanetary disk
• Multiple paths of deuterium fractionation in protoplanetary disks
• Dynamical stellar masses of pre-main sequence stars in Lupus and Taurus obtained with ALMA surveys in comparison with stellar evolutionary models
• Tracing pebble drift and trapping using radial carbon depletion profiles in protoplanetary disks
• Consistent dust and gas models for protoplanetary disks IV. A panchromatic view of protoplanetary disks
• C${}^{18}$O emission as an effective measure of gas masses of protoplanetary disks
• The Perseus ALMA Chemical Survey (PEACHES). III. Sulfur-bearing species tracing accretion and ejection processes in young protostars
• The Anatomy of an Unusual Edge-on Protoplanetary Disk. II. Gas temperature and a warm outer region
• If you like C/O variations, you should have put a ring on it
• Investigating the asymmetric chemistry in the disk around the young star HD 142527
• Molecular Mapping of DR Tau's Protoplanetary Disk, Envelope, Outflow, and Large-Scale Spiral Arm
• Analysing the SEDs of protoplanetary disks with machine learning
• An ALMA Survey of Chemistry in Disks around M4-M5 Stars
• A major asymmetric ice trap in a planet-forming disk IV. Nitric oxide gas and a lack of CN tracing sublimating ices and a C/O ratio $<1$
• Protoplanetary disks: Sensitivity of the chemical composition to various model parameters
• A 3mm chemical exploration of small organics in Class I YSOs
• Planet formation in the PDS 70 system: Constraining the atmospheric chemistry of PDS 70b and c

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