Distortion of Magnetic Fields in a Starless Core VI: Application of Flux Freezing Model and Core Formation of FeSt 1-457

Abstract

Observational data for the hourglass-like magnetic field toward the starless dense core FeSt 1-457 were compared with a flux freezing magnetic field model (Myers et al. 2018). Fitting of the observed plane-of-sky magnetic field using the flux freezing model gave a residual angle dispersion comparable with the results based on a simple three-dimensional parabolic model. The best-fit parameters for the flux freezing model were a line-of-sight magnetic inclination angle of ${\gamma }_{\mathrm{mag}}=35^{\circ }\pm 15^{\circ }$ and a core center to ambient (background) density contrast of ${\rho }_{\mathrm{c}}/{\rho }_{\mathrm{bkg}}=75$. The initial density for core formation (${\rho }_0$) was estimated to be ${\rho }_{\mathrm{c}}/75=4670$ cm${}^{-3}$, which is about one order of magnitude higher than the expected density ($\sim 300$ cm${}^{-3}$) for the inter-clump medium of the Pipe Nebula. FeSt 1-457 is likely to have been formed from the accumulation of relatively dense gas, and the relatively dense background column density of $A_V\simeq 5$ mag supports this scenario. The initial radius (core formation radius) $R_0$ and the initial magnetic field strength $B_0$ were obtained to be 0.15 pc ($1.64R$) and $10.8-14.6$ $\mu$G, respectively. We found that the initial density ${\rho }_0$ is consistent with the mean density of the nearly critical magnetized filament with magnetic field strength $B_0$ and radius $R_0$. The relatively dense initial condition for core formation can be naturally understood if the origin of the core is the fragmentation of magnetized filaments.

arXiv commentAccepted for publication in ApJ

References in corpus (62)

• Theory of Star Formation
• Control of star formation by supersonic turbulence
• From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from the Herschel Gould Belt survey
• Density, Velocity, and Magnetic Field Structure in Turbulent Molecular Cloud Models
• Characterizing interstellar filaments with Herschel in IC5146
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
• Radiative torques: Analytical Model and Basic Properties
• Radiative Torques on Interstellar Grains: I. Superthermal Spinup
• The Millennium Arecibo 21-cm Absorption Line Survey. IV. Statistics of Magnetic Field, Column Density, and Turbulence
• Radiative Torques on Interstellar Grains: II. Grain Alignment
• A Catalogue of Optically Selected Cores
• 2MASS wide field extinction maps - I. The Pipe nebula
• Characterizing the properties of nearby molecular filaments observed with Herschel
• An Extinction Threshold for Protostellar Cores in Ophiuchus
• First Observations of the Magnetic Field Geometry in Pre-stellar Cores
• Magnetic Field Diagnostics Based on Far-Infrared Polarimetry: Tests Using Numerical Simulations
• Theoretical Models of Polarized Dust Emission from Protostellar Cores
• Interstellar Extinction Law toward the Galactic Center II: V, J, H, and Ks Bands
• Near Infrared Imaging Survey of Bok Globules: Density Structure
• The Pipe Nebula as seen with Herschel: Formation of filamentary structures by large-scale compression ?
• Quiescent Cores and the Efficiency of Turbulence-Accelerated, Magnetically Regulated Star Formation
• Optical polarimetry toward the Pipe nebula: Revealing the importance of the magnetic field
• On the radiation driven alignment of dust grains: Detection of the polarization hole in a starless core
• Ambipolar Drift in a Turbulent Medium
• Distances and Kinematics of Gould Belt Star-Forming Regions with Gaia DR2 results
• Detailed Interstellar Polarimetric Properties of the Pipe Nebula at Core Scales
• Magnetic field evolution in Bok globules
• Enhancement of Ambipolar Diffusion Rates through Field Fluctuations
• Grain Alignment in Starless Cores
• The nature of the dense core population in the Pipe Nebula: A survey of NH3, CCS, and HC5N molecular line emission
• A Spitzer Census of Star Formation Activity in the Pipe Nebula
• Magnetohydrostatic Equilibrium Structure and Mass of Filamentary Isothermal Cloud Threaded by Lateral Magnetic Field
• Looking into the hearts of Bok globules: MM and submm continuum images of isolated star-forming cores
• Magnetically-Regulated Fragmentation Induced by Nonlinear Flows and Ambipolar Diffusion
• JCMT BISTRO Survey observations of the Ophiuchus Molecular Cloud: Dust grain alignment properties inferred using a Ricean noise model
• Exploring Magnetic Field Structure in Star-Forming Cores with Polarization of Thermal Dust Emission
• A technique for constraining the driving scale of turbulence and a modified Chandrasekhar-Fermi method
• A Far-Infrared Survey of Molecular Cloud Cores
• The Dynamical State of the Starless Dense Core FeSt 1-457: A Pulsating Globule?
• The Dynamical State fo the Starless Dense Core FeSt 1-457: A Pulsating Globule?
• Nonlinear Evolution of Gravitational Fragmentation Regulated by Magnetic Fields and Ambipolar Diffusion
• Alignment of Outflows with Magnetic Fields in Cloud Cores
• Magnetic Field Structure in Spheroidal Star-Forming Clouds
• Distortion of Magnetic Fields in a Starless Core: Near-Infrared Polarimetry of FeSt 1-457
• Fragmentation of Filamentary Cloud Permeated by Perpendicular Magnetic Field
• Star-forming filament models
• Formation of dense structures induced by filament collisions. Correlation of density, kinematics and magnetic field in the Pipe nebula
• Nothing to hide: An X-ray survey for young stellar objects in the Pipe Nebula
• A Mathematical Model for an Hourglass Magnetic Field
• Distortion of Magnetic Fields in a Starless Core II: 3D Magnetic Field Structure of FeSt 1-457
• How the power spectrum of dust continuum images may hide the presence of a characteristic filament width
• Smoke in the Pipe Nebula: dust emission and grain growth in the starless core FeSt 1-457
• The Herschel View of Star Formation
• Distortion of Magnetic Fields in a Starless Core IV: Magnetic Field Scaling on Density and Mass-to-flux Ratio Distribution in FeSt 1-457
• Submillimeter Polarimetry with PolKa, a reflection-type modulator for the APEX telescope
• Induced Core Formation Time in Subcritical Magnetic Clouds by Large-Scale Trans-Alfvénic Flows
• Distortion of Magnetic Fields in a Starless Core III: Polarization--Extinction Relationship in FeSt 1-457
• A Survey of Magnetic Field Strengths in the Envelopes of Molecular Clouds via the 18 cm OH Zeeman Effect
• A correlation between chemistry, polarization and dust properties in the Pipe Nebula starless core FeSt 1-457
• Fragmentation of Filamentary Cloud Permeated by Perpendicular Magnetic Field II. Dependence on the Initial Density Profile
• Distortion of Magnetic Fields in a Starless Core V: Near-infrared and Submillimeter Polarization in FeSt 1-457

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• Magnetic Properties of Star-Forming Dense Cores
• Three-dimensional magnetic fields of molecular clouds
• Magnetic Field Structure in Spheroidal Star-Forming Clouds. II. Estimating Field Structure from Observed Maps
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• Fitting an Analytic Magnetic Field to a Prestellar Core
• Distortion of Magnetic Fields in the Dense Core CB81 (L1774, Pipe 42) in the Pipe Nebula
• Distortion of Magnetic Fields in the Dense Core SL42 (CrA-E) in the Corona Australis Molecular Cloud Complex
• Grain alignment and dust evolution physics with polarisation (GRADE-POL). I. Dust polarisation modelling for isolated starless cores