17:15 〜 18:30
[PPS15-P03] Modeling of Dust Emission from Disk Surrounding HD 142527
キーワード：HD 142527, Dust emission, Modeling
We model the 870 μm dust continuum emission from the azimuthally-asymmetric disk around HD 142527 based on ALMA Cycle 0 observation. The disk is inflated, inclined by 27° to the line of sight, and its major axis is along PA = 341°. High resolution images in NIR scattered light (Fukagawa et al. (2006)) and MIR thermal radiation (Fujiwara et al. (2006)) indicate that the eastern side (PA = 341° − 161°) of the disk is farther whereas the western side (PA = 161° − 341°) is closer to us. In our model, we assume the radial surface density distribution of the dust disk to be gaussian, and the dust size distribution follows a-3.5, where amax = 1 mm. At the observation wavelength, scattering opacity is 10 times larger than absorption opacity in our model (Aikawa & Nomura (2006)). Dust density, temperature, and radiative energy density of the disk are determined by M1 approximation method (Kanno, Harada, Hanawa (2013)).
The peak surface densities of dust, Σ0, at PA = 21° (the brightest region) and PA = 221° (the faintest region) are 0.8 g cm-2 and 0.008 g cm-2, which are consistent with Muto et al. (2015). We cannot reproduce, however, the observed surface brightness in the northwestern region (PA = 291° − 351°), i.e., the near side with about 80% brightness of PA = 21°, even with Σ0 = 1.25 g cm-2. This is due to: (i) the heavy scattering; (ii) the dependence of the disk surface brightness on the veiwing angle. We solve the problem by reducing the scattering opacity to 10% of its original value. Subsequently, the Σ0 values for the brighter lopsided region (PA = 291° − 71°) become about 50% lower than their original values, while for the remaining optically thin regions Σ0 values do not change significantly. We will also discuss how such a scattering opacity can be realized.
The peak surface densities of dust, Σ0, at PA = 21° (the brightest region) and PA = 221° (the faintest region) are 0.8 g cm-2 and 0.008 g cm-2, which are consistent with Muto et al. (2015). We cannot reproduce, however, the observed surface brightness in the northwestern region (PA = 291° − 351°), i.e., the near side with about 80% brightness of PA = 21°, even with Σ0 = 1.25 g cm-2. This is due to: (i) the heavy scattering; (ii) the dependence of the disk surface brightness on the veiwing angle. We solve the problem by reducing the scattering opacity to 10% of its original value. Subsequently, the Σ0 values for the brighter lopsided region (PA = 291° − 71°) become about 50% lower than their original values, while for the remaining optically thin regions Σ0 values do not change significantly. We will also discuss how such a scattering opacity can be realized.