Effect of dust size and structure on scattered-light images of protoplanetary discs
Effect of dust size and structure on scattered-light images of protoplanetary discs
复制标题
尘埃尺寸和结构对原行星盘散射光图像的影响
DOI：
10.1093/mnras/stz662
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发表时间：
2019
影响因子：
4.8
通讯作者：
S.
中科院分区：
文献类型：
--
作者：
Tazaki;R.;Tanaka;H.;Muto;T.;Kataoka;A.;& Okuzumi;S.
我们通过辐射传输模拟研究了不同尘埃大小和结构的原行星盘在近红外波段的散射光特性。我们发现，只要尘埃半径大于波长，就可以通过测量尘埃盘偏振度来探测不同的尘埃结构。当半径大于观测波长时，对于多孔性很强的尘埃聚集体，圆盘散射光将高度偏振，而更致密的尘埃结构往往表现出较低的偏振分数。其次，研究了单体半径和分形维数对散射光颜色的影响。我们发现，在瑞利制度之外，作为分形维数或单体半径的增加，在近红外波长的有效的双链体的颜色从蓝色到红色。我们的研究结果表明，光盘显示灰色或略蓝色的颜色和高偏振分数在近红外波长可能是由含有亚微米级单体的大的多孔聚集体的存在下解释。
We study scattered-light properties of protoplanetary discs at near-infrared wavelengths for various dust size and structure by performing radiative transfer simulations. We show that different dust structures might be probed by measuring disc polarization fraction as long as the dust radius is larger than the wavelength. When the radius is larger than observing wavelength, disc scattered light will be highly polarized for highly porous dust aggregates, whereas more compact dust structure tends to show low polarization fraction. Next, roles of monomer radius and fractal dimension for scattered-light colours are studied. We find that, outside the Rayleigh regime, as fractal dimension or monomer radius increases, colours of the effective albedo at near-infrared wavelengths vary from blue to red. Our results imply that discs showing grey or slightly blue colours and high polarization fraction in near-infrared wavelengths might be explained by the presence of large porous aggregates containing sub-micron-sized monomers.