Magnetic Fields and Star Formation around H II Regions: The S235 Complex
Magnetic Fields and Star Formation around H II Regions: The S235 Complex
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DOI：
10.3847/1538-4357/abe9b1
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发表时间：
2021-03
期刊：
影响因子：
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通讯作者：
R. Devaraj;D. Clemens;L. Dewangan;A. Luna;T. Ray;J. Mackey
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作者：
R. Devaraj;D. Clemens;L. Dewangan;A. Luna;T. Ray;J. Mackey
磁场在星星的形成过程中无处不在，也是必不可少的。特别是，它们在调节恒星形成过程中的作用，需要很好地理解。在这项研究中，我们目前的磁场性质对S235复杂的近红外（NIR）H-波段偏振观测，获得与Mimir和波利坎仪器。我们选择了375个背景恒星在现场通过盖亚距离和近红外颜色的结合。从星光偏振角推断的天空平面（POS）磁场取向揭示了一个弯曲的形态跟踪的H II区域的球壳。普朗克追踪到的大尺度磁场平行于银河平面。我们确定了11个密集的团块，使用1.1毫米的尘埃排放，质量在33和525 M之间。团平均POS磁场强度估计在36和121 μG之间，平均值为1.65 μG。团块的质量通量比被发现是亚临界的湍流阿尔文马赫数小于1，表明一个强磁化区域。团块显示磁场强度与密度的比例关系，幂律指数为0.52 ± 0.07，类似于双极扩散模型。我们的研究结果表明，S235复合体是一个恒星反馈触发新恒星的区域，磁场调节新星星形成的速率。
Magnetic fields are ubiquitous and essential in star formation. In particular, their role in regulating formation of stars across diverse environments like H ii regions needs to be well understood. In this study, we present magnetic field properties toward the S235 complex using near-infrared (NIR) H-band polarimetric observations, obtained with the Mimir and POLICAN instruments. We selected 375 background stars in the field through combination of Gaia distances and extinctions from NIR colors. The plane-of-sky (POS) magnetic field orientations inferred from starlight polarization angles reveal a curved morphology tracing the spherical shell of the H ii region. The large-scale magnetic field traced by Planck is parallel to the Galactic plane. We identified 11 dense clumps using 1.1 mm dust emission, with masses between 33 and 525 M ⊙. The clump-averaged POS magnetic field strengths were estimated to be between 36 and 121 μG, with a mean of ∼65 μG. The mass-to-flux ratios for the clumps are found to be subcritical with turbulent Alfvén Mach numbers less than 1, indicating a strongly magnetized region. The clumps show scaling of magnetic field strength versus density with a power-law index of 0.52 ± 0.07, similar to ambipolar diffusion models. Our results indicate that the S235 complex is a region where stellar feedback triggers new stars, and the magnetic fields regulate the rate of new star formation.