Dust Polarization in Four Protoplanetary Disks at 3 mm: Further Evidence of Multiple Origins
Dust Polarization in Four Protoplanetary Disks at 3 mm: Further Evidence of Multiple Origins
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DOI：
10.3847/2041-8213/ab1e46
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发表时间：
2019-05
期刊：
影响因子：
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通讯作者：
Rachel E. Harrison;L. Looney;I. Stephens;Zhi-Yun Li;Haifeng Yang;A. Kataoka;R. Harris;W. Kwon;T. Muto;M. Momose
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文献类型：
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作者：
Rachel E. Harrison;L. Looney;I. Stephens;Zhi-Yun Li;Haifeng Yang;A. Kataoka;R. Harris;W. Kwon;T. Muto;M. Momose
我们提出了四个II类原行星盘（DG Tau，哈洛6-13，RY Tau，和MWC 480）采取的阿塔卡马大型毫米/亚毫米阵列（阿尔马）在3毫米的偏振观测分为两个不同的类别：方位角偏振（DG Tau和哈洛6-13）和偏振平行于磁盘短轴（RY Tau和MWC 480）。在毫米和亚毫米波长的磁盘偏振机制负责目前正在辩论中。在这封信中，我们调查了两种机制能够产生偏振尘埃排放的磁盘：自散射和晶粒排列的辐射各向异性。DG Tau和哈洛6-13的偏振形态与从辐射对准所预期的大致一致（尽管辐射对准仍然不能解释在这些盘中看到的所有特征），而RY Tau和MWC 480与自散射更一致。极化形态的这种变化可能提供了来源之间尘埃颗粒大小差异的证据。
We present polarimetric observations of four Class II protoplanetary disks (DG Tau, Haro 6–13, RY Tau, and MWC 480) taken with the Atacama Large Millimeter/submillimeter Array (ALMA) at 3 mm. The polarization morphologies observed fall into two distinct categories: azimuthal polarization (DG Tau and Haro 6–13) and polarization parallel to the disk minor axis (RY Tau and MWC 480). The mechanisms responsible for disk polarization at millimeter and submillimeter wavelengths are currently under debate. In this Letter, we investigate two mechanisms capable of producing polarized dust emission in disks: self-scattering and grain alignment to the radiation anisotropy. The polarization morphologies of DG Tau and Haro 6–13 are broadly consistent with that expected from radiation alignment (though radiative alignment still does not account for all of the features seen in these disks), while RY Tau and MWC 480 are more consistent with self-scattering. Such a variation in the polarized morphology may provide evidence of dust grain size differences between the sources.