VLA and NOEMA view of the Bok Globule CB 17: the starless nature of a proposed FHSC candidate

Abstract

We use 3mm continuum NOEMA and NH${}_3$ VLA observations towards the First Hydrostatic Core (FHSC) candidate CB 17 MMS to reveal the dust structure and gas properties down to 600-1,100 au scales and constrain its evolutionary stage. We do not detect any compact source at the previously identified 1.3 mm point source, despite expecting a minimum signal-to-noise of 9. The gas traced by NH${}_3$ exhibits subsonic motions, with an average temperature of 10.4 K. A fit of the radial column density profile derived from the ammonia emission finds a flat inner region of radius $\sim$1,800 au and a central density of $\sim$6$\times 10^5$ cm${}^{-3}$. Virial and density structure analysis reveals the core is marginally bound (${\alpha }_{vir}$= 0.73). The region is entirely consistent with a young starless core, hence ruling out CB 17 MMS as a FHSC candidate. Additionally, the core exhibits a velocity gradient aligned with the major axis, showing an arc-like structure in the p-v diagram and an off-center region with high-velocity dispersion caused by two distinct velocity peaks. These features could be due to interaction with the nearby outflow, which appears to deflect due to the dense gas near the NH${}_3$ column density peak. We investigate the specific angular momentum profile of the starless core, finding that it aligns closely with previous studies of such radial profiles in Class 0 sources. This similarity to more evolved objects suggests that motions at 1,000 au scales are determined by large-scale dense cloud motions and may be preserved through the early stages of star formation.

References in corpus (52)

• Cold Dark Clouds: The Initial Conditions for Star Formation
• Systematic Molecular Differentiation in Starless Cores
• How to Calculate Molecular Column Density
• Observing the gas temperature drop in the high-density nucleus of L 1544
• Protostellar disk formation and transport of angular momentum during magnetized core collapse
• An Ammonia Spectral Atlas of Dense Cores in Perseus
• Dynamics and Depletion in Thermally Supercritical Starless Cores
• Survey of ortho-H2D+(1_{1,0}-1_{1,1}) in dense cloud cores
• The Green Bank Ammonia Survey (GAS): First Results of NH3 mapping the Gould Belt
• Turbulent Molecular Cloud Cores: Rotational Properties
• The Different Structures of the Two Classes of Starless Cores
• The Origin and Formation of the Circumstellar Disk
• Herschel observations of B1-bS and B1-bN: two first hydrostatic core candidates in the Perseus star-forming cloud
• The Initial Conditions of Clustered Star Formation I: NH3 Observations of Dense Cores in Ophiuchus
• The enigmatic core L1451-mm: a first hydrostatic core? or a hidden VeLLO?
• Radiation Magnetohydrodynamics Simulation of Proto-Stellar Collapse: Two-Component Molecular Outflow
• A Candidate Detection of the First Hydrostatic Core
• L1448 IRS2E: A candidate first hydrostatic core
• An analytic column density profile to fit prestellar cores
• OVRO N2H+ Observations of Class 0 Protostars: Constraints on the Formation of Binary Stars
• The evolutionary state of the southern dense core Cha-MMS1
• Nonlinear Evolution of Global Hydrodynamic Shallow-Water Instability in Solar Tachocline
• Detection of a Bipolar Molecular Outflow Driven by a Candidate First Hydrostatic Core
• Looking into the hearts of Bok globules: MM and submm continuum images of isolated star-forming cores
• Nascent bipolar outflows associated with the first hydrostatic core candidates Barnard 1b-N and 1b-S
• Gas-phase CO depletion and N2H+ abundances in starless cores
• Dark cloud cores and gravitational decoupling from turbulent flows
• Angular momentum profiles of Class 0 protostellar envelopes
• ALMA observations of the young protostellar system Barnard 1b: signatures of an incipient hot corino in B1b-S
• An Ammonia Spectral Map of the L1495-B218 Filaments in the Taurus Molecular Cloud : I. Physical Properties of Filaments and Dense cores
• SMA and Spitzer Observations of Bok Glouble CB17: A Candidate First Hydrostatic Core?
• A Pre-Protostellar Core in L1551
• Gas and dust temperature in pre-stellar cores revisited: New limits on cosmic-ray ionization rate
• How Starless Are Starless Cores?
• The specific angular momentum radial profile in dense cores: improved initial conditions for disk formation
• Mass Assembly of Stellar Systems and their Evolution with the SMA - 1.3 mm Subcompact Data Release
• The Dynamics of the Envelope Surrounding the Protostar HH 211-mm
• ALMA detections of the youngest protostars in Ophiuchus
• Probing the Earliest Stage of Protostellar Evolution -- Barnard 1-bN and Barnard 1-bS
• ALMA observations of envelopes around first hydrostatic core candidates
• Investigating the Complex Velocity Structures within Dense Molecular Cloud Cores with GBT-Argus
• Rotating filament in Orion B: Do cores inherit their angular momentum from their parent filament?
• Kinematics of a young low-mass star forming core: Understanding the evolutionary state of the First Core Candidate L1451-mm
• A low-velocity bipolar outflow from a deeply embedded object in Taurus revealed by the Atacama Compact Array
• Mapping the prestellar core Ophiuchus D (L1696A) in ammonia
• The Earliest Phases of Star formation (EPoS): Temperature, density, and kinematic structure of the star-forming core CB 17
• High-resolution ammonia mapping of the very young protostellar core Chamaeleon-MMS1
• Synthetic molecular line observations of the first hydrostatic core from chemical calculations
• Mapping the H${}_2$D${}^{+}$ and N${}_2$H${}^{+}$ emission towards prestellar cores. Testing dynamical models of the collapse using gas tracers
• The dynamically young outflow of the Class 0 protostar Cha-MMS1
• A turbulent origin for the complex envelope kinematics in the young low-mass core Per-Bolo 58
• What can the SEDs of first hydrostatic core candidates reveal about their nature?

Cited by in corpus (3)

• An Interferometric View of H-MM1. I. Direct Observation of NH3 Depletion
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Evidence for a Molecular Jet Launched at an Unprecedented Early Phase of Protostellar evolution
• Insights into the first and second hydrostatic core stages from numerical simulations