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<p>Original polarimetric data of stars in the vicinity of the Bok globule CB67, located at the periphery of the nearby star-forming region ρ Oph, are considered. Variations of the visual extinction <i>A</i><sub><i>V</i></sub> in the plane of the sky and with distance d are analyzed using various data sources. It is found that a jump in <i>A</i><sub><i>V</i></sub> of about 0<sup>m</sup>.8 at a distance of <i>d</i> ≈ 140 pc is associated with the neutral wind of the Upper Scorpius part of the Sco–Cen OB association. In the outer layers of CB67 (d = 140 pc), this jump increases by more than 0<sup>m</sup>.5–1. The derived parameters of interstellar polarization for 66 stars around CB67 are supplemented with modern data on their distances and interstellar extinction. It is found that the magnetic-field direction in the immediate vicinity (several arcminutes) of CB67 has a position angle θ<sub><i>B</i></sub> = 90 ± 20°, which differs significantly from the mean orientation in a wider (several-degree) region, where <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\overline{\uptheta }\)</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mi mathvariant="normal">θ</mi> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation> ≈ 60° . It is noted that for CB67 the value of θ<sub><i>B</i></sub> agrees better than <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\overline{\uptheta }\)</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mi mathvariant="normal">θ</mi> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation> with the usual correlations between the magnetic-field (polarization) direction and the directions of maximum elongation of clouds and their rotation axes. For CB67, the latter are characterized by θ<sub><i>L</i></sub> ≈ 107° and θ<sub><i>R</i></sub> = 112°, respectively. With the exception of a few stars, the observed degree of polarization P correlates fairly well with <i>A</i><sub><i>V</i></sub>, and the obtained ratios P/<i>A</i><sub><i>V</i></sub> = 0.5–2%/mag are typical of the diffuse interstellar medium.</p>

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Interstellar Polarization Around the Bok Globule CB67

  • 期刊论文

  • 发表日期：

    2025年12月1日

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  • M. S. Prokopjeva,
  • H. A. Krayani,
  • V. B. Il’in,
  • T. Kondratieva,
  • A. K. Sen,
  • R. Gupta

摘要

Original polarimetric data of stars in the vicinity of the Bok globule CB67, located at the periphery of the nearby star-forming region ρ Oph, are considered. Variations of the visual extinction AV in the plane of the sky and with distance d are analyzed using various data sources. It is found that a jump in AV of about 0m.8 at a distance of d ≈ 140 pc is associated with the neutral wind of the Upper Scorpius part of the Sco–Cen OB association. In the outer layers of CB67 (d = 140 pc), this jump increases by more than 0m.5–1. The derived parameters of interstellar polarization for 66 stars around CB67 are supplemented with modern data on their distances and interstellar extinction. It is found that the magnetic-field direction in the immediate vicinity (several arcminutes) of CB67 has a position angle θB = 90 ± 20°, which differs significantly from the mean orientation in a wider (several-degree) region, where \(\overline{\uptheta }\) θ ¯ ≈ 60° . It is noted that for CB67 the value of θB agrees better than \(\overline{\uptheta }\) θ ¯ with the usual correlations between the magnetic-field (polarization) direction and the directions of maximum elongation of clouds and their rotation axes. For CB67, the latter are characterized by θL ≈ 107° and θR = 112°, respectively. With the exception of a few stars, the observed degree of polarization P correlates fairly well with AV, and the obtained ratios P/AV = 0.5–2%/mag are typical of the diffuse interstellar medium.