Molecular Cloud Cores with High Deuterium Fraction: Nobeyama Single-Pointing Survey

Abstract

We present the results of a single-pointing survey of 207 dense cores embedded in Planck Galactic Cold Clumps distributed in five different environments ($\lambda$ Orionis, Orion A, B, Galactic plane, and high latitudes) to identify dense cores on the verge of star formation for the study of the initial conditions of star formation. We observed these cores in eight molecular lines at 76-94 GHz using the Nobeyama 45-m telescope. We find that early-type molecules (e.g., CCS) have low detection rates and that late-type molecules (e.g., N${}_2$H${}^{+}$, c-C${}_3$H${}_2$) and deuterated molecules (e.g., N${}_2$D${}^{+}$, DNC) have high detection rates, suggesting that most of the cores are chemically evolved. The deuterium fraction (D/H) is found to decrease with increasing distance, indicating that it suffers from differential beam dilution between the D/H pair of lines for distant cores ($>$1 kpc). For $\lambda$ Orionis, Orion A, and B located at similar distances, D/H is not significantly different, suggesting that there is no systematic difference in the observed chemical properties among these three regions. We identify at least eight high D/H cores in the Orion region and two at high latitudes, which are most likely to be close to the onset of star formation. There is no clear evidence of the evolutionary change in turbulence during the starless phase, suggesting that the dissipation of turbulence is not a major mechanism for the beginning of star formation as judged from observations with a beam size of 0.04 pc.

arXiv comment55 pages, 12 Figures, 8 Tables, accepted for publication in ApJS

References in corpus (79)

• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• Theory of Star Formation
• From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from the Herschel Gould Belt survey
• Cold Dark Clouds: The Initial Conditions for Star Formation
• Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
• The Spitzer Space Telescope Survey of the Orion A & B Molecular Clouds - Part I: A Census of Dusty Young Stellar Objects and a Study of their Mid-IR Variability
• Probing the evolutionary status of starless cores through N2H+ and N2D+ observations
• How to Calculate Molecular Column Density
• Molecular ions in L1544. II. The ionization degree
• The initial conditions of stellar protocluster formation. I. A catalogue of Spitzer dark clouds
• Observing the gas temperature drop in the high-density nucleus of L 1544
• Young Stellar Objects in the Gould Belt
• A Parallax-based Distance Estimator for Spiral Arm Sources
• The Aquila prestellar core population revealed by Herschel
• Hierarchical fragmentation and differential star formation in the Galactic "Snake": infrared dark cloud G11.11-0.12
• Molecular Evolution and Star Formation: From Prestellar Cores to Protostellar Cores
• Molecular Evolution in Collapsing Prestellar Cores
• A Catalogue of Optically Selected Cores
• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• Molecular Evolution in Collapsing Prestellar Cores III: Contraction of A Bonnor-Ebert Sphere
• Chemistry in Infrared Dark Cloud Clumps: a Molecular Line Survey at 3 mm
• A Catalog of MSX Infrared Dark Cloud Candidates
• The ALMA Survey of 70 $\mu$m dark High-mass clumps in Early Stages (ASHES). I. Pilot Survey: Clump Fragmentation
• Planck Early Results: The Galactic Cold Core Population revealed by the first all-sky survey
• Evolution of Chemistry and Molecular Line Profile during Protostellar Collapse
• Fragmentation of Molecular Clumps and Formation of Protocluster
• The Gould's Belt Distances Survey (GOBELINS). V. Distances and Kinematics of the Perseus molecular cloud
• Hipparcos distances of Ophiuchus and Lupus cloud complexes
• Galactic cold cores III. General cloud properties
• Depletion and low gas temperature in the L183 prestellar core : the N2H+ - N2D+ tool
• The N2D+/N2H+ ratio as an evolutionary tracer of Class 0 protostars
• The California Molecular Cloud
• An all-sky Support Vector Machine selection of WISE YSO Candidates
• A Massive Prestellar Clump Hosting no High-Mass Cores
• The unexpectedly large proportion of high-mass star-forming cores in a Galactic mini-starburst
• Detection of D2H+ in the Dense Interstellar Medium
• Deuteration as an evolutionary tracer in massive-star formation
• The Gould's Belt Distances Survey (GOBELINS). IV. Distance, Depth and Kinematics of the Taurus Star-Forming Region
• Molecular Evolution in Collapsing Prestellar Cores II: The Effect of Grain-surface Reactions
• Chemistry and Dynamics in Pre-Protostellar Cores
• Planck 2015 results. XXVIII. The Planck Catalogue of Galactic Cold Clumps
• Modeling the Physical Structure of the Low Density Pre-protostellar Core Lynds 1498
• Searching for massive pre--stellar cores through observations of N2H+ and N2D+
• Identification of Young Stellar Object candidates in the $Gaia$ DR2 x AllWISE catalogue with machine learning methods
• The MYStIX InfraRed-Excess Source Catalog
• Infall Signatures in a Prestellar Core embedded in the High-Mass 70 $\mu$m Dark IRDC G331.372-00.116
• Digital Spectro-Correlator System for the Atacama Compact Array of the Atacama Large Millimeter/submillimeter Array
• Astrometry of H${}_2$O Masers in Nearby Star-Forming Regions with VERA. III. IRAS 22198+6336 in L1204G
• The TOP-SCOPE survey of Planck Galactic Cold Clumps: Survey overview and results of an exemplar source, PGCC G26.53+0.17
• N2H+ and HC3N Observations of the Orion A Cloud
• Chemical evolution in the early phases of massive star formation II: Deuteration
• Hyperfine structure in the J = 1-0 transitions of DCO+, DNC, and HN13C: astronomical observations and quantum-chemical calculations
• The Initial Conditions of Clustered Star Formation. II. N2H+ Observations of the Ophiuchus B Core
• DNC/HNC Ratio of Massive Clumps in Early Evolutionary Stages of High-Mass Star Formation
• Formation and Collapse of Quiescent Cloud Cores Induced by Dynamic Compressions
• Astrochemical Properties of Planck Cold Clumps
• A New 100-GHz Band Two-Beam Sideband-Separating SIS Receiver for Z-Machine on the NRO 45-m Radio Telescope
• DNC/HNC and N2D+/N2H+ ratios in high-mass star forming cores
• Deuterium Fractionation as an Evolutionary Probe in the Infrared Dark Cloud G28.34+0.06
• SCOPE: SCUBA-2 Continuum Observations of Pre-protostellar Evolution - Survey Description and Compact Source Catalogue
• Molecular Line Observations of a Carbon-Chain-Rich Core L492
• Mapping Observations of DNC and HN^13C in Dark Cloud Cores
• Planck Cold Clumps in the $\lambda$ Orionis complex. II. Environmental effects on core formation
• Deuterium Fractionation as an Evolutionary Probe in Massive Proto-stellar/cluster Cores
• Gravitationally unstable condensations revealed by ALMA in the TUKH122 prestellar core in the Orion A cloud
• Distance and extinction determination for APOGEE stars with Bayesian method
• The chemical structure of young high-mass star-forming clumps: (I) Deuteration
• ALMA Observations of the IRDC Clump G34.43+00.24 MM3: Complex Organic and Deuterated Molecules
• Open clusters: III. Fundamental parameters of B stars in NGC 6087, NGC 6250, NGC 6383 and NGC 6530. B type stars with circumstellar envelopes
• Galactic cold cores IX. Column density structures and radiative transfer modelling
• Towards a census of the Galactic anticentre star clusters II: exploring lower overdensities
• Estimating distance, pressure, and dust opacity using submillimeter observations of self-gravitating filaments
• Chemical Variation in Molecular Cloud Cores in the Orion A Cloud. II
• ALMA Observations of the IRDC Clump G34.43+00.24 MM3: DNC/HNC Ratio
• The distance to the young cluster NGC 7129 and its age
• ALMA ACA and Nobeyama observations of two Orion cores in deuterated molecular lines
• Chemical evolution of the HC3N and N2H+ molecules in dense cores of the Vela C giant molecular cloud complex

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• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP) II. Survey overview: a first look at 1.3 mm continuum maps and molecular outflows
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): A Hot Corino Survey toward Protostellar Cores in the Orion Cloud
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Detection of extremely high density compact structure of prestellar cores and multiple substructures within
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• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): A forming quadruple system with continuum `ribbons' and intricate outflows
• DCO${}^{+}$ and DCN 1-0 survey toward a sample of Planck cold clumps
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