Gas phase Elemental abundances in Molecular cloudS (GEMS) I. The prototypical dark cloud TMC 1

Abstract

GEMS is an IRAM 30m Large Program whose aim is determining the elemental depletions and the ionization fraction in a set of prototypical star-forming regions. This paper presents the first results from the prototypical dark cloud TMC 1. Extensive millimeter observations have been carried out with the IRAM 30m telescope (3mm and 2mm) and the 40m Yebes telescope (1.3cm and 7mm) to determine the fractional abundances of CO, HCO+, HCN, CS, SO, HCS+, and N2H+ in three cuts which intersect the dense filament at the well-known positions TMC 1-CP, TMC 1-NH3, and TMC 1-C, covering a visual extinction range from Av~3 to ~20mag. Two phases with differentiated chemistry can be distinguished: i) the translucent envelope with molecular hydrogen densities of (1-5)x10${}^3$ cm${}^{-3}$; and ii) the dense phase, located at Av>10mag, with molecular hydrogen densities >10${}^4$ cm${}^{-3}$. Observations and modeling show that the gas phase abundances of C and O progressively decrease along the C+/C/CO transition zone where C/H~8x10${}^{-5}$ and C/O~0.8-1, until the beginning of the dense phase at Av~10 mag. This is consistent with the grain temperatures being below the CO evaporation temperature in this region. In the case of sulfur, a strong depletion should occur before the translucent phase where we estimate a S/H~(0.4 - 2.2) x10${}^{-6}$, an abundance ~7-40 times lower than the solar value. A second strong depletion must be present during the formation of the thick icy mantles to achieve the values of S/H measured in the dense cold cores (S/H~8x10${}^{-8}$). Based on our chemical modeling, we constrain the value of ${\zeta }_{{\mathrm{H}}_2}$ to ~(0.5 - 1.8) x10${}^{-16}$ s${}^{-1}$ in the translucent cloud.

arXiv comment26 pages, 20 figures, A&A in press

References in corpus (54)

• emcee: The MCMC Hammer
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• The Herschel-SPIRE instrument and its in-flight performance
• A computer program for fast non-LTE analysis of interstellar line spectra
• From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from the Herschel Gould Belt survey
• A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
• A model for atomic and molecular interstellar gas: The Meudon PDR code
• Large-Scale Structure of the Molecular Gas in Taurus Revealed by High Linear Dynamic Range Spectral Line Mapping
• Rotational quenching of CO due to H${}_2$ collisions
• Molecular ions in L1544. II. The ionization degree
• Cosmic-ray ionization of molecular clouds
• Chemistry of Dark Clouds: Databases, Networks, and Models
• On the Formation of CO2 and Other Interstellar Ices
• On the reservoir of sulphur in dark clouds : chemistry and elemental abundance reconciled
• The Degree of CO Depletion in Pre-stellar Cores
• Herschel/HIFI observations of interstellar OH+ and H2O+ towards W49N: a probe of diffuse clouds with a small molecular fraction
• The dust temperature distribution in prestellar cores
• Surface chemistry in the interstellar medium - I - H2 formation by Langmuir-Hinshelwood and Eley-Rideal mechanisms
• The cosmic ray ionization rate in the Galactic disk, as determined from observations of molecular ions
• The Green Bank Ammonia Survey (GAS): First Results of NH3 mapping the Gould Belt
• Low sulfur depletion in the Horsehead PDR
• Sulfur depletion in dense clouds and circumstellar regions I. H2S ice abundance and UV-photochemical reactions in the H2O-matrix
• Protostellar Disk Formation Enabled by Removal of Small Dust Grains
• Comparative Chemistry of Diffuse Clouds II: CN, HCN, HNC, CH3CN & N2H+
• The interstellar gas-phase chemistry of HCN and HNC
• A New Reference Chemical Composition for TMC-1
• The Five College Radio Astronomy Observatory CO Mapping Survey of the Taurus Molecular Cloud
• Evolution of OH and CO-dark Molecular Gas Fraction Across a Molecular Cloud Boundary In Taurus
• Sulphur-bearing molecules in diffuse molecular clouds: new results from SOFIA/GREAT and the IRAM 30 m telescope
• First results from the Herschel Gould Belt Survey in Taurus
• Cosmic-ray ionisation in collapsing clouds
• Mapping Large-Scale CO Depletion in a Filamentary Infrared Dark Cloud
• Comparative chemistry of diffuse clouds III: sulfur-bearing molecules
• The penetration of FUV radiation into molecular clouds
• The Dust Emissivity Spectral Index in the Starless Core TMC-1C
• Profiling filaments: comparing near-infrared extinction and submillimetre data in TMC-1
• Modelling the sulphur chemistry evolution in Orion KL
• Ionization fraction and the enhanced sulfur chemistry in Barnard 1
• Parameterizing the interstellar dust temperature
• Gas-phase CO depletion and N2H+ abundances in starless cores
• TMC-1C: an accreting starless core
• H2S in the L1157-B1 Bow shock
• Structure Function Scaling of a 2MASS Extinction Map of Taurus
• High spatial resolution imaging of SO and H2CO in AB Auriga: the first SO image in a transitional disk
• Structure and stability in TMC-1: analysis of NH${}_3$ molecular line and Herschel continuum data
• Clustering the Orion B giant molecular cloud based on its molecular emission
• Spectral Tomography for the Line-of-Sight Structures of the Taurus Molecular Cloud 1
• Chemical complexity in local diffuse and translucent clouds: ubiquitous l-C3H and CH3CN, a detection of HC3N and an upper limit on the abundance of CH2CN
• Chemical study of intermediate-mass (IM) Class 0 protostars. CO depletion and N2H+ deuteration
• Chemical modeling of the L1498 and L1517B prestellar cores: CO and HCO+ depletion
• N${}_2$H${}^{+}$ and N${}^{15}$NH${}^{+}$ towards the prestellar core 16293E in L1689N
• The Effect of Far-infrared Radiation on the Hyperfine Anomaly of the OH 18 cm Transition
• Dynamics, CO depletion, and deuterium fractionation of the dense condensations within the fragmented prestellar core Orion B9-SMM 6
• VLA and GBT Observations of Orion B (NGC 2024, W12) : Photo-dissociation Region Properties and Magnetic field

Cited by in corpus (61)

• Yebes 40 m radio telescope and the broad band NANOCOSMOS receivers at 7 mm and 3 mm for line surveys
• Early Science from GOTHAM: Project Overview, Methods, and the Detection of Interstellar Propargyl Cyanide (HCCCH${}_2$CN) in TMC-1
• Discovery of two isomers of ethynyl cyclopentadiene in TMC-1: Abundances of CCH and CN derivatives of hydrocarbon cycles
• 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
• Efficiency of non-thermal desorptions in cold-core conditions. Testing the sputtering of grain mantles induced by cosmic rays
• Photoprocessing of H2S on dust grains: building S chains in translucent clouds and comets
• Abundances of sulphur molecules in the Horsehead nebula. First NS+ detection in a photodissociation region
• Gas phase Elemental abundances in Molecular cloudS (GEMS). IV. Observational results and statistical trends
• The first steps of Interstellar Phosphorus Chemistry
• Bottlenecks to interstellar sulfur chemistry: Sulfur-bearing hydrides in UV-illuminated gas and grains
• AB Aur, a Rosetta stone for studies of planet formation (I): chemical study of a planet-forming disk
• Molecular Line Observations in Two Dusty Star-Forming Galaxies at z = 6.9
• Probing the physics of star formation (ProPStar): I. First resolved maps of the electron fraction and cosmic-ray ionization rate in NGC 1333
• LOC program for line radiative transfer
• Gas-phase Elemental abundances in Molecular cloudS (GEMS) III. Unlocking the CS chemistry: the CS+O reaction
• Evolutionary view through the starless cores in Taurus: deuteration in TMC 1-C and TMC 1-CP
• The PDR structure and kinematics around the compact HII regions S235A and S235C with [CII], [13CII], [OI] and HCO+ line profiles
• Gas phase Elemental abundances in Molecular cloudS (GEMS) V. Methanol in Taurus
• Formation of S-bearing complex organic molecules in interstellar clouds via ice reactions with C2H2, HS, and atomic H
• The SVS13-A Class I chemical complexity as revealed by S-bearing species. SOLIS XIII
• Gas phase Elemental abundances in Molecular cloudS (GEMS) VI. A sulphur journey across star-forming regions: study of thioformaldehyde emission
• AB Aur, a Rosetta stone for studies of planet formation (II): H${}_2$S detection and sulfur budget
• On the density regime probed by HCN emission
• Modelling methanol and hydride formation in the JWST Ice Age era
• Non-ideal MHD simulations of subcritical prestellar cores with non-equilibrium chemistry
• Cyanopolyyne chemistry in the L1544 prestellar core: new insights from GBT observations
• Unusually high HCO+/CO ratios in and outside supernova remnant W49B
• A 3mm chemical exploration of small organics in Class I YSOs
• Linking the dust and chemical evolution: Taurus and Perseus -- New collisional rates for HCN, HNC, and their C, N, and H isotopologues
• Anatomy of the Class I protostar L1489 IRS with NOEMA -- I. Disk, streamers, outflow(s) and bubbles at 3mm
• 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
• Chemical compositions of five Planck cold clumps
• The Effects of Cosmic Rays on the Chemistry of Dense Cores
• Modelling the evolution and influence of dust in cosmological simulations that include the cold phase of the interstellar medium
• Gas accretion within the dust cavity in AB Aur
• Ice origins of OCS and chemistry of CS2-bearing ice mantles
• Design and Implementation of a New Apparatus for Astrochemistry: Kinetic Measurements of the CH + OCS Reaction and Frequency Comb Spectroscopy in a Cold Uniform Supersonic Flow
• Astrochemical Bistability: Autocatalysis in Oxygen Chemistry
• Chemical variations across the TMC-1 boundary: molecular tracers from translucent phase to dense phase
• XRISM insights for interstellar Sulfur
• First detection of HS2 in a cold dark cloud
• Density Functional Theory Calculations on the Interstellar Formation of Biomolecules
• The sulfur plume in the Horsehead nebula: New detections of S${}_2$H, SH${}^{+}$, and CO${}^{+}$
• A quest for sulfur-bearing refractory species. Identification of CaS in the interstellar medium
• Gas phase Elemental abundances in Molecular cloudS (GEMS). IX. Deuterated compounds of H2S in starless cores
• Relative Alignment Between Magnetic Fields and Molecular Gas Structure in Molecular Clouds
• One of Everything: The Breakthrough Listen Exotica Catalog
• Gas phase Elemental abundances in Molecular cloudS (GEMS). X. Observational effects of turbulence on the chemistry of molecular clouds
• New Bistable Solutions in Molecular Cloud Chemistry: Nitrogen and Carbon Autocatalysis
• The rich molecular environment of the luminous blue variable star AFGL 2298
• NOEMA complementarity with NIKA2
• Gas phase Elemental abundances in Molecular cloudS (GEMS) VIII. Unlocking the CS chemistry: the CH + S$\to$ CS + H and C${}_2$ + S$\to$ CS + C reactions
• Gas-phase Elemental abundances in Molecular cloudS (GEMS) XI. The evolution of HCN, HNC, and N2H+ isotopic ratios in starless cores
• Chemical constraints on the dynamical evolution of the cold core L694
• Fine-tuning the complex organic molecule formation: sulfur and CO ice as regulators of surface chemistry
• High deuteration of methanol in L1544
• NIKA2 observations of starless cores in Taurus and Perseus
• 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
• Chemistry of Dark Molecular Clouds