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We investigate the dust and gas distribution in the disk around HD 142527 based on ALMA observations of dust continuum emissions, 13CO J = 3-2 and C18O J = 3-2. The disk shows strong azimuthal asymmetry in the dust continuum emission, while gas emission is more symmetric. In this paper, we investigate how gas and dust are distributed in the dust-bright northern part of the disk and in the dust-faint southern part. We construct two axisymmetric disk models. One reproduces the radial profiles of the continuum and the velocity moments 0 and 1 of CO lines in the north, and the other reproduces those in the south. We have found that the dust is concentrated in a narrow ring of ~50 au width (in FWHM; wd = 30 au in our parameter definition), located at ~170-200 au from the central star. The dust particles are strongly concentrated in the north. We have found that the dust surface density contrast between the north and the south amounts to ~70. Compared to the dust, the gas distribution is more extended in the radial direction. We find that the gas component extends at least from ~100 au to ~250 au from the central star, and there should also be tenuous gas remaining inside and outside of these radii. The azimuthal asymmetry of gas distribution is much smaller than dust. The gas surface density differs only by a factor of ~3-10 between the north and south. Hence, the gas-todust ratio strongly depends on the location of the disk: ~30 at the location of the peak of dust distribution in the south and ~3 at the location of the peak of dust distribution in the north. Despite large uncertainties, we infer that the overall gas-to-dust ratio is ~10-30, indicating that the gas depletion may already have been under way. [ABSTRACT FROM AUTHOR]

Coronagraphic imagery of the circumstellar disk around HD169142 in H-band polarized intensity (PI) with Subaru/HiCIAO is presented. The emission scattered by dust particles at the disk surface in 0".2 ≤ r ≤ 1".2, or 29 ≤ r ≤ 174 au, is successfully detected. The azimuthally averaged radial profile of the PI shows a double power-law distribution, in which the PIs in r=29-52 au and r=81.2-145 au respectively show r-3 dependence. These two power-law regions are connected smoothly with a transition zone (TZ), exhibiting an apparent gap in r = 40-70 au. The PI in the inner power-law region shows a deep minimum whose location seems to coincide with the point source at λ = 7mm. This can be regarded as another sign of a protoplanet in the TZ. The observed radial profile of the PI is reproduced by aminimally flaring disk with an irregular surface density distribution, an irregular temperature distribution, or with a combination of both. The depletion factor of surface density in the inner power-law region (r < 50 au) is derived to be ≥0.16 from a simple model calculation. The obtained PI image also shows small-scale asymmetries in the outer power-law region. Possible origins for these asymmetries include corrugation of the scattering surface in the outer region, and a shadowing effect by a puffed-up structure in the inner power-law region. [ABSTRACT FROM AUTHOR]