Investigating dust trapping in transition disks with millimeter-wave polarization

Abstract

Spatially resolved polarized (sub-)mm emission has been observed for example in the protoplanetary disk around HL Tau. Magnetically aligned grains are commonly interpreted as the source of polarization. However, self-scattering by large dust grains with a high enough albedo is another polarization mechanism, becoming a compelling method independent of the spectral index to constrain the dust grain size in protoplanetary disks. We study the dust polarization at mm wavelength in the dust trapping scenario proposed for transition disks, when a giant planet opens a gap in the disk. We investigate the characteristic polarization patterns and their dependence on disk inclination, dust size evolution, planet position, and observing wavelength. We combine two-dimensional hydrodynamical simulations of planet-disk interactions with self-consistent dust growth models. These size-dependent dust density distributions are used for follow-up three-dimensional radiative transfer calculations to predict the polarization degree at ALMA bands due to scattered thermal emission. We find that the polarization pattern of a disk with a planetary gap after 1 Myr of dust evolution shows a distinctive three ring structure. Two narrow inner rings are located at the planet gap edges. For increasing observing wavelengths all three rings slightly change their position, where the innermost and outermost rings move inward. This distance is detectable comparing the results at ALMA bands 3, 6 and 7. Within the highest polarized intensity regions the polarization vectors are oriented in the azimuthal direction. For an inclined disk there is an interplay between polarization originating from a flux gradient and inclination-induced quadrupole polarization. For intermediate inclined transition disks the polarization degree is as high as ~ 2% at band 3, which is well above the detection limit of future ALMA observations.

11 pages, 16 figures, accepted for publication in A&A

References in corpus (10)

• Gas- and dust evolution in protoplanetary disks
• Particle Stirring in Turbulent Gas Disks: Including Orbital Oscillations
• Ring shaped dust accumulation in transition disks
• Tracing Magnetic Fields with Aligned Grains
• Gaps, Rings, and Non-Axisymmetric Structures in Protoplanetary Disks - From Simulations to ALMA Observations
• Shadows cast by a warp in the HD 142527 protoplanetary disk
• Spatially Resolved Magnetic Field Structure in the Disk of a T Tauri Star
• Grain Alignment and Polarized Emission from Magnetized T Tauri Disks
• The Magnetic Field in the Class 0 Protostellar Disk of L1527
• Effect of dust grain porosity on the appearance of protoplanetary disks

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• Interferometric observations of magnetic fields in forming stars
• ALMA observations of dust polarization and molecular line emission from the Class 0 protostellar source Serpens SMM1
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• Retrieving Dust Grain Sizes from Photopolarimetry: An Experimental Approach
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• Filling in the Gaps: Can Gravitationally Unstable Discs Form the Seeds of Gas Giant Planets?
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• ALMA 873 $\mu$m Polarization Observations of the PDS~70 Disk
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