Near-infrared Polarization from Unresolved Disks around Brown Dwarfs and Young Stellar Objects
Near-infrared Polarization from Unresolved Disks around Brown Dwarfs and Young Stellar Objects
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DOI：
10.3847/1538-4357/ac415c
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发表时间：
2021-12
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影响因子：
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通讯作者：
D. Clemens;T. Pillai;A. Rilinger;C. Espaillat
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作者：
D. Clemens;T. Pillai;A. Rilinger;C. Espaillat
宽视场近红外（NIR）偏振测量被用来检查两颗褐矮星（BD）和两颗嵌入金牛座Heiles Cloud 2（HCl 2）暗分子云中的年轻恒星（YSO）以及位于HCl 2后面的众多恒星周围的盘系统。倾斜的磁盘表现出固有的近红外偏振由于光球光的散射，这是可检测的，即使是未解决的系统。从背景星星信息中确定的HCl 2中的磁性排列尘埃中去除偏振贡献后，从一个BD（ITG 17）和两个YSO（ITG 15，ITG 25）的盘系统中检测到显著的固有偏振，但从另一个BD（2 M0444）中没有检测到。ITG 17 BD显示了从近红外光谱和已发表的阿塔卡马大型毫米/亚毫米阵列尘埃连续成像推断的盘方向的良好一致性。ITG 17也被发现存在于一个5200 Au宽的双星（或等级四星星系统）中，与ITG 15 YSO磁盘系统。从ITG 15和ITG 17的NIR推断的盘取向彼此平行并且垂直于局部磁场方向。系统的多样性和大BD盘的性质可能是由于在磁场和原恒星盘不对准的环境中形成的。
Wide-field near-infrared (NIR) polarimetry was used to examine disk systems around two brown dwarfs (BDs) and two young stellar objects (YSOs) embedded in the Heiles Cloud 2 (HCl2) dark molecular cloud in Taurus as well as numerous stars located behind HCl2. Inclined disks exhibit intrinsic NIR polarization due to scattering of photospheric light, which is detectable even for unresolved systems. After removing polarization contributions from magnetically aligned dust in HCl2 determined from the background star information, significant intrinsic polarization was detected from the disk systems of one BD (ITG 17) and both YSOs (ITG 15, ITG 25), but not from the other BD (2M0444). The ITG 17 BD shows good agreement of the disk orientation inferred from the NIR and from published Atacama Large Millimeter/submillieter Array dust continuum imaging. ITG 17 was also found to reside in a 5200 au wide binary (or hierarchical quad star system) with the ITG 15 YSO disk system. The inferred disk orientations from the NIR for ITG 15 and ITG 17 are parallel to each other and perpendicular to the local magnetic field direction. The multiplicity of the system and the large BD disk nature could have resulted from formation in an environment characterized by misalignment of the magnetic field and the protostellar disks.