Distortion of Magnetic Fields in a Starless Core: Near-infrared Polarimetry of FeSt 1–457

• 長田, 哲也

  Department of Astronomy, The University of Tokyo

• Tamura, Motohide

  Department of Astronomy, The University of Tokyo･National Astronomical Observatory of Japan･Astrobiology Center of NINS

• Kusakabe, Nobuhiko

  Department of Astronomy, The University of Tokyo

• Nakajima, Yasushi

  Hitotsubashi University

• Kwon, Jungmi

  Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency

• Nagayama, Takahiro

  Kagoshima University

• Nagata, Tetsuya

  Kyoto University

• Tomisaka, Kohji

  National Astronomical Observatory of Japan

• Tatematsu, Ken’ichi

  National Astronomical Observatory of Japan

抄録

Magnetic fields are believed to play an important role in controlling the stability and contraction of the dense condensations of gas and dust that lead to the formation of stars and planetary systems. In the present study, the magnetic field of FeSt 1–457, a cold starless molecular cloud core, was mapped on the basis of the polarized near-infrared light from 185 background stars after being dichroically absorbed by dust aligned with the magnetic field in the core. A distinct "hourglass-shaped" magnetic field was identified in the region of the core, and was interpreted as the first evidence of a magnetic field structure distorted by mass condensation in a starless core. The steep curvature of the magnetic field lines obtained in the present study indicates that the distortion was mainly created during the formation phase of the dense core. The derived mass-to-magnetic flux ratio indicates that the core is in a magnetically supercritical state. However, the stability of the core can be considered to be in a nearly critical state if the additional contributions from the thermal and turbulent support are included. Further diffusion of the magnetic field and/or turbulent dissipation would cause the onset of the dynamical collapse of the core. The geometrical relationship between the direction of the magnetic field lines and the elongation of the core was found to be in good agreement with theoretical predictions for the formation of Sun-like stars under the influence of a magnetic field.

収録刊行物

• The Astrophysical Journal

  The Astrophysical Journal 845 32-, 2017-08-09

  American Astronomical Society

キーワード

• dust, extinction
• ISM: clouds
• polarization
• stars: formation

詳細情報

• CRID: 1050002213759994880
• NII論文ID: 120006782214
• ISSN: 15384357
• ISSN: 0004637X
• ISSN: http://id.crossref.org/issn/0004637X
• DOI: 10.3847/1538-4357/aa7d58
• HANDLE: 2433/245471
• Web Site: http://stacks.iop.org/0004-637X/845/i=1/a=32/pdf
• Web Site: http://stacks.iop.org/0004-637X/845/i=1/a=32?key=crossref.98e3b60d13ce66c8933ee81eb3ffedad
• Web Site: https://iopscience.iop.org/article/10.3847/1538-4357/aa7d58
• Web Site: https://iopscience.iop.org/article/10.3847/1538-4357/aa7d58/pdf
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
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  • CiNii Articles
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