Open AccessDistortion of Magnetic Fields in Barnard 335
Author(s) -
Ryo Kandori,
Masao Saito,
Motohide Tamura,
Kohji Tomisaka,
Toshiro Matsumoto,
Ryo Tazaki,
T. Nagata,
Nobuhiko Kusakabe,
Yasushi Nakajima,
Jungmi Kwon,
Takahiro Nagayama,
Ken’ichi Tatematsu
Publication year - 2020
Publication title -
astrophysical journal/the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.3847/1538-4357/ab6f07
Subject(s) - physics , magnetic field , astrophysics , stars , polarization (electrochemistry) , magnetic structure , magnetization , quantum mechanics , chemistry
In this study, the detailed magnetic field structure of the dense protostellar core Barnard 335 (B335) was revealed, based on near-infrared polarimetric observations of background stars to measure dichroically polarized light produced by magnetically aligned dust grains in the core. Magnetic fields pervading B335 were mapped using 24 stars after subtracting unrelated ambient polarization components, revealing that they have an axisymmetrically distorted hourglass-shaped structure toward the protostellar core. On the basis of simple two- and three-dimensional magnetic field modeling, magnetic inclination angles in the plane-of-sky and line-of-sight directions were determined to be 90° ± 7° and 50° ± 10°, respectively. The total magnetic field strength of B335 was determined to be 30.2 ± 17.7 μ G. The critical mass of B335, evaluated using both magnetic and thermal/turbulent support against collapse, was determined to be M cr = 3.37 ± 0.94 M ⊙ , which is identical to the observed core mass of M core = 3.67 M ⊙ . We thus concluded that B335 started its contraction from a condition near equilibrium. We found a linear relationship in the polarization versus extinction diagram, up to A V ∼ 15 mag toward the stars with the greatest obscuration, which verified that our observations and analysis provide an accurate depiction of the core.