Nobeyama Survey of Inward Motions toward Cores in Orion Identified by SCUBA-2

Abstract

In this study, 36 cores (30 starless and 6 protostellar) identified in Orion were surveyed to search for inward motions. We used the Nobeyama 45 m radio telescope, and mapped the cores in the $J=1\to 0$ transitions of HCO${}^{+}$, H${}^{13}$CO${}^{+}$, N${}_2$H${}^{+}$, HNC, and HN${}^{13}$C. The asymmetry parameter $\delta V$, which was the ratio of the difference between the HCO${}^{+}$ and H${}^{13}$CO${}^{+}$ peak velocities to the H${}^{13}$CO${}^{+}$ line width, was biased toward negative values, suggesting that inward motions were more dominant than outward motions. Three starless cores (10% of all starless cores surveyed) were identified as cores with blue-skewed line profiles (asymmetric profiles with more intense blue-shifted emission), and another two starless cores (7%) were identified as candidate blue-skewed line profiles. The peak velocity difference between HCO${}^{+}$ and H${}^{13}$CO${}^{+}$ of them was up to 0.9 km s${}^{-1}$, suggesting that some inward motions exceeded the speed of sound for the quiescent gas ($\sim 10-17$ K). The mean of $\delta V$ of the five aforementioned starless cores was derived to be $-$0.5$\pm$0.3. One core, G211.16$-$19.33North3, observed using the ALMA ACA in DCO${}^{+}$ $J=3\to 2$ exhibited blue-skewed features. Velocity offset in the blue-skewed line profile with a dip in the DCO${}^{+}$ $J=3\to 2$ line was larger ($\sim 0.5$ km s${}^{-1}$) than that in HCO${}^{+}$ $J=1\to 0$ ($\sim 0.2$ km s${}^{-1}$), which may represent gravitational acceleration of inward motions. It seems that this core is at the last stage in the starless phase, judging from the chemical evolution factor version 2.0 (CEF2.0).

arXiv comment45 pages, 28 figures, ApJ in press

References in corpus (60)

• Theory of Star Formation
• Herschel view of the Taurus B211/3 filament and striations: Evidence of filamentary growth?
• The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
• Probing the evolutionary status of starless cores through N2H+ and N2D+ observations
• Tracing the Mass during Low-Mass Star Formation. II. Modelling the Submillimeter Emission from Pre-Protostellar Cores
• N2H+ and C18O Depletion in a Cold Dark Cloud
• A Search for Infall Motions Toward Nearby Young Stellar Objects
• Molecular Evolution in Collapsing Prestellar Cores
• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• The Herschel Orion Protostar Survey: Spectral Energy Distributions and Fits Using a Grid of Protostellar Models
• The initial conditions of isolated star formation - VI. SCUBA mapping of prestellar cores
• Molecular Evolution in Collapsing Prestellar Cores III: Contraction of A Bonnor-Ebert Sphere
• A Survey for Infall Motions toward Starless Cores. I. CS (2-1) and N${}_2$H${}^{+}$ (1-0) Observations
• Dense core formation by fragmentation of velocity-coherent filaments in L1517
• Planck Early Results: The Galactic Cold Core Population revealed by the first all-sky survey
• The Origin of Massive Stars: The Inertial-Inflow Model
• The Circumstellar Environment of High Mass Protostellar Objects. III Evidence of Infall?
• The N2D+/N2H+ ratio as an evolutionary tracer of Class 0 protostars
• A Parallactic Distance of 389 +24/-21 parsecs to the Orion Nebula Cluster from Very Long Baseline Array Observations
• The Dynamical State of Barnard 68: A Thermally Supported, Pulsating Dark Cloud
• On-The-Fly Observing System of the Nobeyama 45-m and ASTE 10-m Telescopes
• The dynamics of collapsing cores and star formation
• Filamentary Fragmentation and Accretion in High-Mass Star-Forming Molecular Clouds
• Chemistry and Dynamics in Pre-Protostellar Cores
• Gravity Driven Magnetic Field at ~1000 au Scales in High-mass Star Formation
• Modeling the Physical Structure of the Low Density Pre-protostellar Core Lynds 1498
• Digital Spectro-Correlator System for the Atacama Compact Array of the Atacama Large Millimeter/submillimeter Array
• Infall Signatures in a Prestellar Core embedded in the High-Mass 70 $\mu$m Dark IRDC G331.372-00.116
• Detection of Infall in the Protostar B335 with ALMA
• Abundant cyanopolyynes as a probe of infall in the Serpens South cluster-forming region
• The distance to the Orion Nebula Cluster
• The central 1000 AU of a pre-stellar core revealed with ALMA. I. 1.3 mm continuum observations
• The TOP-SCOPE survey of Planck Galactic Cold Clumps: Survey overview and results of an exemplar source, PGCC G26.53+0.17
• How to Identify Pre-Protostellar Cores
• Velocity-coherent Filaments in NGC 1333: Evidence for Accretion Flow?
• Does Infall End Before the Class I Stage?
• A Far-Infrared Survey of Molecular Cloud Cores
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP) II. Survey overview: a first look at 1.3 mm continuum maps and molecular outflows
• Formation and Collapse of Quiescent Cloud Cores Induced by Dynamic Compressions
• Astrochemical Properties of Planck Cold Clumps
• FRagmentation and Evolution of dense cores Judged by ALMA (FREJA). I (Overview). Inner $\sim$1000 au structures of prestellar/protostellar cores in Taurus
• The Dynamical State fo the Starless Dense Core FeSt 1-457: A Pulsating Globule?
• The Dynamical State of the Starless Dense Core FeSt 1-457: A Pulsating Globule?
• Gaia Stellar Kinematics in the Head of the Orion A Cloud: Runaway Stellar Groups and Gravitational Infall
• 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
• Digging into the Interior of Hot Cores with ALMA (DIHCA). I. Dissecting the High-mass Star-Forming Core G335.579-0.292 MM1
• Constraining the Infalling Envelope Models of Embedded Protostars: BHR 71 and its Hot Corino
• Asymmetric Line Profiles in Dense Molecular Clumps Observed in MALT90: Evidence for Global Collapse
• Planck Cold Clumps in the $\lambda$ Orionis complex. II. Environmental effects on core formation
• Line Profiles of Cores within Clusters. III. What is the most reliable tracer of core collapse in dense clusters?
• Evidence for Inflow in High-Mass Star-Forming Clumps
• Dichotomy in the Dynamical Status of Massive Cores in Orion
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Detection of extremely high density compact structure of prestellar cores and multiple substructures within
• Molecular Cloud Cores with High Deuterium Fraction: Nobeyama Single-Pointing Survey
• The chemical structure of young high-mass star-forming clumps: (I) Deuteration
• A Low-mass Cold and Quiescent Core Population in a Massive Star Protocluster
• ALMA ACA and Nobeyama observations of two Orion cores in deuterated molecular lines
• Planck Cold Clumps in the lambda Orionis Complex. III. A chemical probe of stellar feedback on cores in the lambda Orionis cloud
• Molecular Cloud Cores with High Deuterium Fractions: Nobeyama Mapping Survey

Cited by in corpus (1)

• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): A forming quadruple system with continuum `ribbons' and intricate outflows