Sulfur chemistry in protoplanetary disks: CS and H2CS

Abstract

The nature and abundance of sulfur chemistry in protoplanetary disks (PPDs) may impact the sulfur inventory on young planets and therefore their habitability. PPDs also present an interesting test bed for sulfur chemistry models, since each disk present a diverse set of environments. In this context, we present new sulfur molecule observations in PPDs, and new S-disk chemistry models. With ALMA we observed the CS 5-4 rotational transition toward five PPDs (DM Tau, DO Tau, CI Tau, LkCa 15, MWC 480), and the CS 6-5 transition toward three PPDs (LkCa 15, MWC 480 and V4046 Sgr). Across this sample, CS displays a range of radial distributions, from centrally peaked, to gaps and rings. We also present the first detection in PPDs of ${}^{13}$CS 6-5 (LkCa 15 and MWC 480), C${}^{34}$S 6-5 (LkCa 15), and H${}_2$CS $8_{17}-7_{16}$, $9_{19}-8_{18}$ and $9_{18}-8_{17}$ (MWC 480) transitions. Using LTE models to constrain column densities and excitation temperatures, we find that either ${}^{13}$C and ${}^{34}$S are enhanced in CS, or CS is optically thick despite its relatively low brightness temperature. Additional lines and higher spatial resolution observations are needed to distinguish between these scenarios. Assuming CS is optically thin, CS column density model predictions reproduce the observations within a factor of a few for both MWC 480 and LkCa 15. However, the model underpredicts H${}_2$CS by 1-2 orders of magnitude. Finally, comparing the H${}_2$CS/CS ratio observed toward the MWC~480 disk and toward different ISM sources, we find the closest match with prestellar cores.

arXiv comment33 pages, 34 figures, accepted for publication in ApJ

References in corpus (93)

• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The NumPy array: a structure for efficient numerical computation
• The chemical composition of the Sun
• Gaia Data Release 2. Summary of the contents and survey properties
• scikit-image: Image processing in Python
• 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
• Observations of the Icy Universe
• A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
• Passive irradiated circumstellar disks with an inner hole
• The Mass Dependence Between Protoplanetary Disks and their Stellar Hosts
• Protoplanetary Disk Structures in Ophiuchus
• Accretion Disks around Young Objects. I. The Detailed Vertical Structure
• Rapid Formation of Molecular Clouds and Stars in the Solar Neighborhood
• Star Formation in a Crossing Time
• The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
• The Disk Substructures at High Angular Resolution Project (DSHARP): II. Characteristics of Annular Substructures
• Non-thermal desorption from interstellar dust grains via exothermic surface reactions
• Dynamical Masses of T Tauri Stars and Calibration of PMS Evolution
• The Disk Population of the Taurus Star-Forming Region
• Radiation thermo-chemical models of protoplanetary disks I. Hydrostatic disk structure and inner rim
• On the age of the $\beta$ Pictoris moving group
• Gas and grain chemical composition in cold cores as predicted by the Nautilus 3-phase model
• Probing the structure of protoplanetary disks: a comparative study of DM Tau, LkCa 15 and MWC 480
• A dual-frequency sub-arcsecond study of proto-planetary disks at mm wavelengths: First evidence for radial variations of the dust properties
• Polycylcic Aromatic Hydrocarbons (PAH's) in dense cloud chemistry
• The ancient heritage of water ice in the solar system
• Spectral Energy Distributions of T Tauri and Herbig Ae Disks: Grain Mineralogy, Parameter Dependences, and Comparison with ISO LWS Observations
• A Parametric Modeling Approach to Measuring the Gas Masses of Circumstellar Disks
• The cometary composition of a protoplanetary disk as revealed by complex cyanides
• On the reservoir of sulphur in dark clouds : chemistry and elemental abundance reconciled
• Constraining the X-ray and Cosmic Ray Ionization Chemistry of the TW Hya Protoplanetary Disk: Evidence for a Sub-interstellar Cosmic Ray Rate
• Modeling Sulfur Depletion in Interstellar Clouds
• Photodesorption of water ice: a molecular dynamics study
• Resetting chemical clocks of hot cores based on S-bearing molecules
• Resolving the inner dust disks surrounding LkCa 15 and MWC 480 at mm wavelengths
• The Effects of UV Continuum and Lyman alpha Radiation on the Chemical Equilibrium of T Tauri Disks
• UV photodesorption of methanol in pure and CO-rich ices: desorption rates of the intact molecule and of the photofragments
• Low sulfur depletion in the Horsehead PDR
• Oxygen depletion in dense molecular clouds: a clue to a low O2 abundance?
• Disk Imaging Survey of Chemistry with SMA (DISCS): I. Taurus Protoplanetary Disk Data
• An interferometric study of the low-mass protostar IRAS 16293-2422: small scale organic chemistry
• Sulphur chemistry in the L1544 pre-stellar core
• The ALMA-PILS survey: The sulphur connection between protostars and comets: IRAS 16293-2422 B and 67P/Churyumov-Gerasimenko
• Herschel/HIFI observations of [CII] and [13CII] in PDRs
• Carbon isotope fractionation in protoplanetary disks
• The CN isotopic ratios in comets
• Spitzer IRS Observations of Class I/II Objects in Taurus: Composition and Thermal History of the Circumstellar Ices
• A New Probe of the Planet-Forming Region in T Tauri Disks
• Sulphur-bearing molecules in diffuse molecular clouds: new results from SOFIA/GREAT and the IRAM 30 m telescope
• Disks around CQ Tau and MWC 758: dense PDR or gas dispersal?
• A sensitive survey for 13CO, CN, H2CO and SO in the disks of T Tauri and Herbig Ae stars
• The chemistry of multiply deuterated molecules in protoplanetary disks. I. The outer disk
• The negligible photodesorption of methanol ice and the active photon-induced desorption of its irradiation products
• The Structure of the Evolved Circumbinary Disk around V4046 Sgr
• Temperature, Mass and Turbulence: A Spatially Resolved Multi-Band Non-LTE Analysis of CS in TW~Hya
• Cold CO in circumstellar disks: On the effects of photodesorption and vertical mixing
• Deuterium chemistry in protoplanetary disks II The inner 30 AU
• Indirect ultraviolet photodesorption from CO:N2 binary ices - an efficient grain-gas process
• The Distribution and Excitation of CH${}_3$CN in a Solar Nebula Analog
• 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
• 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
• Sulfidic Anion Concentrations on Early Earth for Surficial Origins-of-Life Chemistry
• Chemistry in disks. XI. Sulfur-bearing species as tracers of protoplanetary disk physics and chemistry: the DM Tau case
• The masses of young stars: CN as a probe of dynamical masses
• 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
• First detection of interstellar S2H
• 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
• Dust-driven viscous ring-instability in protoplanetary disks
• CID: Chemistry In Disks VII. First detection of HC3N in protoplanetary disks
• Interferometric imaging of the sulfur-bearing molecules H2S, SO and CS in comet C/1995 O1 (Hale-Bopp)
• On the nature of the transition disk around LkCa 15
• A Disk-based Dynamical Mass Estimate for the Young Binary V4046 Sgr
• The Flying Saucer: Tomography of the thermal and density gas structure of an edge-on protoplanetary disk
• A Method for Deriving Accurate Gas-Phase Abundances for the Multiphase Interstellar Galactic Halo
• First detection of H${}_2$S in a protoplanetary disk. The dense GG Tau A ring
• DCO${}^{+}$, DCN and N${}_2$D${}^{+}$ reveal three different deuteration regimes in the disk around the Herbig Ae star HD163296
• Probing Planet Forming Zones with Rare CO Isotopologues
• Subarcsecond Analysis of Infalling-Rotating Envelope around the Class I Protostar IRAS 04365+2535
• Sulphur monoxide exposes a potential molecular disk wind from the planet-hosting disk around HD100546
• Heterogeneity in ${}^{12}$CO/${}^{13}$CO Ratios Toward Solar-Type Young Stellar Objects
• High spatial resolution imaging of SO and H2CO in AB Auriga: the first SO image in a transitional disk
• Gas density perturbations induced by forming planet(s) in the AS 209 protoplanetary disk as seen with ALMA
• Inner disk structure of the classical T Tauri star LkCa 15
• X-ray radiative transfer in protoplanetary disks - The role of dust and X-ray background fields
• A new study of the chemical structure of the Horsehead nebula: the influence of grain-surface chemistry
• Molecular content of the circumstellar disk in AB Aur: First detection of SO in a circumstellar disk
• Importance of the H2 abundance in protoplanetary disk ices for the molecular layer chemical composition

Cited by in corpus (57)

• 2021 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules
• Molecules with ALMA at Planet-forming Scales (MAPS) I: Program Overview and Highlights
• Astrochemistry and compositions of planetary systems
• Efficient Production of S${}_8$ in Interstellar Ices: The effects of cosmic ray-driven radiation chemistry and non-diffusive bulk reactions
• Gas phase Elemental abundances in Molecular cloudS (GEMS). II. On the quest for the sulphur reservoir in molecular clouds: the $H_{2}S$ case
• Gas phase Elemental abundances in Molecular cloudS (GEMS) VII. Sulfur elemental abundance
• An ALMA Survey of H${}_2$CO in Protoplanetary Disks
• Photoprocessing of H2S on dust grains: building S chains in translucent clouds and comets
• 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
• An unbiased ALMA spectral survey of the LkCa 15 and MWC 480 protoplanetary disks
• Gas phase Elemental abundances in Molecular cloudS (GEMS). IV. Observational results and statistical trends
• Sulphur monoxide emission tracing an embedded planet in the HD 100546 protoplanetary disk
• ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT) V: Sample, overview, and demography of disk molecular emission
• The role of C/O in nitrile astrochemistry in PDRs and planet-forming disks
• Tracing snowlines and C/O ratio in a planet-hosting disk: ALMA molecular line observations towards the HD169142 disk
• AB Aur, a Rosetta stone for studies of planet formation (I): chemical study of a planet-forming disk
• Herbig Stars: A Quarter Century of Progress
• Exploring the link between star and planet formation with Ariel
• ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT): I. CO, CS, CN, and H2CO around DG Tau B
• The Perseus ALMA Chemical Survey (PEACHES). III. Sulfur-bearing species tracing accretion and ejection processes in young protostars
• Chemical survey of Class I protostars with the IRAM-30m
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): I. Detection of New Hot Corinos with ACA
• Gas-phase Elemental abundances in Molecular cloudS (GEMS) III. Unlocking the CS chemistry: the CS+O reaction
• High Spatial Resolution Observations of Molecular Lines towards the Protoplanetary Disk around TW Hya with ALMA
• H2CS deuteration maps towards the pre-stellar core L1544
• Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS): A Panchromatic View of DO Tau's Complex Kilo-au Environment
• Measuring elemental abundance ratios in protoplanetary disks at millimeter wavelengths
• The SVS13-A Class I chemical complexity as revealed by S-bearing species. SOLIS XIII
• AB Aur, a Rosetta stone for studies of planet formation (II): H${}_2$S detection and sulfur budget
• Vertically extended and asymmetric CN emission in the Elias 2-27 protoplanetary disk
• High resolution observations of molecular emission lines toward the CI Tau proto-planetary disc: planet-carved gaps or shadowing?
• A 3mm chemical exploration of small organics in Class I YSOs
• ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT) III: The interplay between gas and dust in the protoplanetary disk of DG Tau
• H${}_2$S observations in young stellar disks in Taurus
• Classification of X-ray Flare Driven Chemical Variability in Protoplanetary Disks
• An unbiased NOEMA 2.6 to 4 mm survey of the GG Tau ring: First detection of CCS in a protoplanetary disk
• SO2 and OCS toward high-mass protostars: A comparative study between ice and gas
• Probing the kinematics and chemistry of the hot core Mon R 2 IRS 3 using ALMA observations
• Physical conditions for dust grain alignment in Class 0 protostellar cores I. Observations of dust polarization and molecular irradiation tracers
• Formation of carbonyl sulfide (OCS) via SH radicals in interstellar CO-rich ice under dense cloud conditions
• An SMA Survey of Chemistry in Disks around Herbig AeBe Stars
• PRODIGE -- Planet-forming disks in Taurus with NOEMA. I. Overview and first results for 12CO, 13CO, and C18O
• ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT). IV. Thioformaldehyde (H${}_2$CS) in protoplanetary disks: spatial distributions and binding energies
• Multi-frequency analysis of the ALMA and VLA high resolution continuum observations of the substructured disc around CI Tau. Preference for sub-mm-sized low-porosity amorphous carbon grains
• Constraints on the gas-phase C/O ratio of DR Tau's outer disk from CS, SO, and C${}_2$H observations
• PRODIGE VI -- Envelope to Disk with NOEMA: VI. The Missing Sulfur Problem
• A major asymmetric ice trap in a planet-forming disk: II. prominent SO and SO2 pointing to C/O < 1
• exoALMA XIX: Confirmation of Non-thermal Line Broadening in the DM Tau Protoplanetary Disk
• Molecules with ALMA at Planet-forming Scales (MAPS) III: Characteristics of Radial Chemical Substructures
• Formation of thiocarbonic acid (H${}_2$CS${}_3$) -- the sulfur counterpart of carbonic acid (H${}_2$CO${}_3$) - in interstellar analog ices
• A SPHERE survey of self-shadowed planet-forming disks
• Updated Ultraviolet Fluorescence Efficiencies of CS: Evidence for Model Discrepancies in the Enhancement of NUV-Derived CS Abundances in Comets
• Molecules with ALMA at Planet-forming Scales (MAPS) XII: Inferring the C/O and S/H ratios in Protoplanetary Disks with Sulfur Molecules
• Modeling the UV-photon irradiation of CS${}_2$-bearing ices in the laboratory with the pyRate gas-grain astrochemical code. New insights into the missing sulfur problem
• Protoplanetary Disk Chemistry
• Ortho-Para Chemistry of H2CO in the Protoplanetary Disk TW Hya
• Characterization of the dust content in the ring around Sz 91: indications for planetesimal formation?