Intrinsic polarisation of elongated porous dust grains

Abstract

ALMA observations revealed recently polarised radiation of several protoplanetary disks in the (sub-)millimetre wavelength range. Besides self-scattering of large particles, thermal emission by elongated grains is a potential source for the detected polarisation signal. We calculate the wavelength dependent absorption and intrinsic polarisation of spheroidally shaped, micrometre and sub-millimetre sized dust grains using the discrete dipole approximation. In particular, we analyse the impact of dust grain porosity which appears to be present in disks when small grains coagulate to form larger aggregates. For the first time our results show that (a) the intrinsic polarisation decreases for increasing grain porosity and (b) the polarisation orientation flips by 90 degree for certain ratios of wavelength to grain size. We present a new method to constrain grain porosity and the grain size in protoplanetary disks using multi-wavelength polarisation observations in the far-infrared to millimetre wavelengths. Finally, we find that moderate grain porosities ($\mathcal{P}\lesssim 0.7$) potentially explain the observed polarisation fraction in the system HD 142527 while highly porous grains ($\mathcal{P}>0.7$) fail unless the grain's axis ratio is extraordinarily large.

arXiv comment10 pages, 10 figures

References in corpus (35)

• Scattering by Interstellar Dust Grains: Optical and Ultraviolet
• Radiative torques: Analytical Model and Basic Properties
• Scattering by Interstellar Dust Grains. II. X-Rays
• Radiative Torques on Interstellar Grains: I. Superthermal Spinup
• Radiative Torques on Interstellar Grains: II. Grain Alignment
• Millimeter-wave polarization of protoplanetary disks due to dust scattering
• Dust coagulation in protoplanetary disks: porosity matters
• Probing dust grain evolution in IM Lupi's circumstellar disc. Multi-wavelength observations and modelling of the dust disc
• The evidence of radio polarization induced by the radiative grain alignment and self-scattering of dust grains in a protoplanetary disk
• Opacity of fluffy dust aggregates
• Radiative grain alignment in protoplanetary disks: Implications for polarimetric observations
• Spatially Resolved Magnetic Field Structure in the Disk of a T Tauri Star
• ALMA Reveals Transition of Polarization Pattern with Wavelength in HL Tau's Disk
• Submillimeter polarization observation of the protoplanetary disk around HD 142527
• ALMA observations of polarization from dust scattering in the IM Lup protoplanetary disk
• ALMA's Polarized View of 10 Protostars in the Perseus Molecular Cloud
• Detection of a Magnetized Disk around a Very Young Protostar
• Submillimetre dust polarisation and opacity in the HD163296 protoplanetary ring system
• Free Collisions in a Microgravity Many-Particle Experiment III: The Collision Behavior of sub-Millimeter-Sized Dust Aggregates
• Two Different Grain Size Distributions within the Protoplanetary Disk around HD 142527 Revealed by ALMA Polarization Observation
• Dust Polarization Toward Embedded Protostars in Ophiuchus with ALMA. I. VLA 1623
• Resolving the polarized dust emission of the disk around the massive star powering the HH~80-81 radio jet
• The optical properties of dust: the effects of composition, size, and structure
• The Magnetic Field in the Class 0 Protostellar Disk of L1527
• ALMA Observations of Polarized 872 $\mu$m Dust Emission from the Protostellar Systems VLA 1623 and L1527
• Light Scattering by Fractal Dust Aggregates. II. Opacity and Asymmetry Parameter
• ALMA Dust Polarization Observations of Two Young Edge-on Protostellar Disks
• Optical polarized phase function of the HR\,4796A dust ring
• Porous dust grains in debris disks
• Effect of dust grain porosity on the appearance of protoplanetary disks
• Magnetic fields in protoplanetary disks: from MHD simulations to ALMA observations
• ALMA High Angular Resolution Polarization Study; An Extremely Young Class 0 Source, OMC-3/MMS 6
• Dust Polarization in Four Protoplanetary Disks at 3 mm: Further Evidence of Multiple Origins
• 3D radiative transfer of intrinsically polarized dust emission based on aligned aspherical grains
• Absorption of crystalline water ice in the far infrared at different temperatures

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• Dust Polarization Toward Embedded Protostars in Ophiuchus with ALMA. III. Survey Overview
• Unveiling Dust Aggregate Structure in Protoplanetary Disks by Millimeter-wave Scattering Polarization
• The Planetary Accretion Shock. II. Grid of Post-Shock Entropies and Radiative Shock Efficiencies for Non-Equilibrium Radiation Transport
• JCMT POL-2 and BISTRO Survey observations of magnetic fields in the L1689 molecular cloud
• Porous Dust Particles in Protoplanetary Disks: Application to the HL Tau Disk
• Magnetic Properties of Dust Grains, Effect of Precession and Radiative Torque Alignment
• Validating Scattering-Induced (Sub)millimeter Disk Polarization through the Spectral Index, Wavelength-Dependent Polarization Pattern, and Polarization Spectrum: The Case of HD 163296
• Impact of Differential Dust Settling on the SED and Polarization: Application to the Inner Region of the HL Tau Disk
• Self-scattering of non-spherical dust grains
• Polarized emission by aligned grains in the Mie regime : application to protoplanetary disks observed by ALMA
• Modeling of the ALMA HL Tau Polarization by Mixture of Grain Alignment and Self-scattering
• Gravitoviscous Protoplanetary Discs with a Dust Component. IV. Disc Outer Edges, Spectral Indices, and Opacity Gaps
• Thermal Emission and Scattering by Aligned Grains: Plane-Parallel Model and Application to Multiwavelength Polarization of the HL Tau Disk
• The JCMT BISTRO Survey: Studying the Complex Magnetic Field of L43
• Polarization from Aligned Dust Grains in the $\beta$ Pic Debris Disk
• First L band detection of hot exozodiacal dust with VLTI/MATISSE
• First BISTRO observations of the dark cloud Taurus L1495A-B10: the role of the magnetic field in the earliest stages of low-mass star formation
• Probing the Temperature Structure of the Inner Region of a Protoplanetary Disk
• Rotational Disruption of Porous Dust Aggregates due to Gas Flow in Protoplanetary Disks
• The JCMT BISTRO-2 Survey: The Magnetic Field in the Center of the Rosette Molecular Cloud
• Dust mass in protoplanetary disks with porous dust opacities
• SOFIA/HAWC+ observations of the Crab Nebula: dust properties from polarised emission
• Synthetic Modelling of Polarized Dust Emission in Intermediate-Mass YSOs: I: Constraining the Role of Iron Inclusions and Inelastic Relaxation on Grain Alignment with ALMA Polarization
• How much large dust could be present in hot exozodiacal dust systems?
• Far-infrared Polarization of the Supernova Remnant Cassiopeia A with SOFIA HAWC+
• Wavelength-dependent far-infrared polarization of HL Tau observed with SOFIA/HAWC+
• Exploring Polarized Millimeter Emission from Protoplanetary Disks with Irregular Dust Grains