Opacity of fluffy dust aggregates

Abstract

Context. Dust grains coagulate to form dust aggregates in protoplanetary disks. Their porosity can be extremely high in the disks. Although disk emission may come from fluffy dust aggregates, the emission has been modeled with compact grains. Aims. We aim to reveal the mass opacity of fluffy aggregates from infrared to millimeter wavelengths with the filling factor ranging from 1 down to $10^{-4}$. Methods. We use Mie calculations with an effective medium theory. The monomers are assumed to be 0.1 $\mu \mathrm{m}$ sized grains, which is much shorter than the wavelengths that we focus on. Results. We find that the absorption mass opacity of fluffy aggregates are characterized by the product $a\times f$, where $a$ is the dust radius and $f$ is the filling factor, except for the interference structure. The scattering mass opacity is also characterized by $af$ at short wavelengths while it is higher in more fluffy aggregates at long wavelengths. We also derive the analytic formula of the mass opacity and find that it reproduces the Mie calculations. We also calculate the expected difference of the emission between compact and fluffy aggregates in protoplanetary disks with a simple dust growth and drift model. We find that compact grains and fluffy aggregates can be distinguished by the radial distribution of the opacity index $\beta$. The previous observation of the radial distribution of $\beta$ is consistent with the fluffy case, but more observations are required to distinguish between fluffy or compact. In addition, we find that the scattered light would be another way to distinguish between compact grains and fluffy aggregates.

16 pages, 17 figures, published in A&A, 568, A42

References in corpus (7)

• Coagulation, fragmentation and radial motion of solid particles in protoplanetary disks
• Structure and evolution of pre-main sequence circumstellar disks
• Dust coagulation in protoplanetary disks: porosity matters
• The shape and composition of interstellar silicate grains
• Testing the theory of grain growth and fragmentation by millimeter observations of protoplanetary disks
• Modeling Porous Dust Grains with Ballistic Aggregates I: Geometry and Optical Properties
• Two different evolutionary types of comets proved by polarimetric and infrared properties of their dust

Cited by in corpus (103)

• Observations of Protoplanetary Disk Structures
• The Disk Substructures at High Angular Resolution Project (DSHARP): V. Interpreting ALMA maps of protoplanetary disks in terms of a dust model
• Sintering-induced Dust Ring Formation in Protoplanetary Disks: Application to the HL Tau Disk
• Millimeter-wave polarization of protoplanetary disks due to dust scattering
• Dust Evolution in Protoplanetary Disks
• Dust masses of young disks: constraining the initial solid reservoir for planet formation
• Molecular abundances and C/O ratios in chemically evolving planet-forming disk midplanes
• The evidence of radio polarization induced by the radiative grain alignment and self-scattering of dust grains in a protoplanetary disk
• Multiwavelength optical properties of compact dust aggregates in protoplanetary disks
• Galaxy Simulation with Dust Formation and Destruction
• Near-infrared scattered light properties of the HR4796A dust ring: a measured scattering phase function from 13.6deg to 166.6deg
• Dust growth and evolution in protoplanetary disks
• Grain size constraints on HL Tau with polarization signature
• Grain Growth in the Circumstellar Disks of the Young Stars CY Tau and DoAr 25
• Submillimeter polarization observation of the protoplanetary disk around HD 142527
• Erosion and the limits to planetesimal growth
• A Close-up View of the Young Circumbinary Disk HD 142527
• The time evolution of dusty protoplanetary disc radii: observed and physical radii differ
• Light scattering by fractal dust aggregates: I. Angular dependence of scattering
• A multi-frequency ALMA characterization of substructures in the GM Aur protoplanetary disk
• Low dust emissivities and radial variations in the envelopes of Class 0 protostars: a signature of early grain growth?
• Tracing water vapor and ice during dust growth
• Estimate on dust scale height from ALMA dust continuum image of the HD 163296 protoplanetary disk
• Two Different Grain Size Distributions within the Protoplanetary Disk around HD 142527 Revealed by ALMA Polarization Observation
• Dust-driven viscous ring-instability in protoplanetary disks
• Super-Rayleigh Slopes in Transmission Spectra of Exoplanets Generated by Photochemical Haze
• Systematic analysis of spectral energy distributions and the dust opacity indices for Class 0 young stellar objects
• Dust traps in the protoplanetary disc MWC 758: two vortices produced by two giant planets?
• The optical properties of dust: the effects of composition, size, and structure
• Size and structures of disks around very low mass stars in the Taurus star-forming region
• Unveiling Dust Aggregate Structure in Protoplanetary Disks by Millimeter-wave Scattering Polarization
• Microphysical Modeling of Mineral Clouds in GJ1214 b and GJ436 b: Predicting Upper Limits on the Cloud-Top Height
• New Constraints From Dust Lines On The Surface Densities Of Protoplanetary Disks
• Effect of dust size and structure on scattered light images of protoplanetary discs
• Light Scattering by Fractal Dust Aggregates. II. Opacity and Asymmetry Parameter
• The Planetary Accretion Shock. II. Grid of Post-Shock Entropies and Radiative Shock Efficiencies for Non-Equilibrium Radiation Transport
• Optical polarized phase function of the HR\,4796A dust ring
• Effects of scattering, temperature gradients, and settling on the derived dust properties of observed protoplanetary disks
• Clouds of Fluffy Aggregates: How They Form in Exoplanetary Atmospheres and Influence Transmission Spectra
• Apparent disk-mass reduction and planetesimal formation in gravitationally unstable disks in Class 0/I YSOs
• The Galilean Satellites Formed Slowly from Pebbles
• ALMA Detection of Extended Millimeter Halos in the HD 32297 and HD 61005 Debris Disks
• Radial variations in grain sizes and dust scale heights in the protoplanetary disk around HD 163296 revealed by ALMA polarization observation
• Investigating dust trapping in transition disks with millimeter-wave polarization
• On the millimetre continuum flux-radius correlation of proto-planetary discs
• Scattering-induced intensity reduction: large mass content with small grains in the inner region of the TW Hya disk
• Does HL Tau Disk Polarization in ALMA Band 3 Come from Radiatively Aligned Grains?
• Intrinsic polarisation of elongated porous dust grains
• Porous Dust Particles in Protoplanetary Disks: Application to the HL Tau Disk
• Accreting protoplanets: Spectral signatures and magnitude of gas and dust extinction at H alpha
• New constraints on the disk characteristics and companion candidates around T Cha with VLT/SPHERE
• Millimeter-sized grains in the protostellar envelopes: where do they come from?
• A large population study of protoplanetary disks: Explaining the millimeter size-luminosity relation with or without sub-structure
• The growth of planets by pebble accretion in evolving protoplanetary discs
• Solving grain size inconsistency between ALMA polarization and VLA continuum in the Ophiuchus IRS 48 protoplanetary disk
• Dust Polarization in Four Protoplanetary Disks at 3 mm: Further Evidence of Multiple Origins
• Cm-wavelength observations of MWC758: resolved dust trapping in a vortex
• What pebbles are made of: Interpretation of the V883 Ori disk
• Depletion of gaseous CO in protoplanetary disks by surface-energy-regulated ice formation
• Support for fragile porous dust in a gravitationally self-regulated disk around IM Lup
• Collisional evolution of dust and water ice in protoplanetary discs during and after an accretion outburst
• Cooling in the shade of warped transition disks
• The impact of dynamic pressure bumps on the observational properties of protoplanetary disks
• Collisional Growth of Icy Dust Aggregates in Disk Formation Stage: Difficulties for Planetesimal Formation via Direct Collisional Growth outside the Snowline
• Thermal conductivity of porous aggregates
• Formation of dust clumps with sub-Jupiter mass and cold shadowed region in gravitationally unstable disk around Class 0/I protostar in L1527 IRS
• Is the gap in the DS Tau disc hiding a planet?
• Disk Masses and Dust Evolution of Protoplanetary Disks Around Brown Dwarfs
• Investigating the gas-to-dust ratio in the protoplanetary disk of HD 142527
• Revealing dust segregation in protoplanetary discs with the help of multi-frequency spectral index maps
• Dust grains cannot grow to millimeter sizes in protostellar envelopes
• Collisional Growth and Fragmentation of Dust Aggregates. II. Mass Distribution of Icy Fragments
• Millimeter Spectral Indices and Dust Trapping By Planets in Brown Dwarf Disks
• Haze Formation on Triton
• (Sub)millimeter Dust Polarization of Protoplanetary Disks from Scattering by Large Millimeter-Sized Irregular Grains
• The Roles of Dust Growth in the Temperature Evolution and Snow Line Migration in Magnetically Accreting Protoplanetary Disks
• Self-scattering in protoplanetary disks with dust settling
• Evolution of dust porosity through coagulation and shattering in the interstellar medium
• Outward Motion of Porous Dust Aggregates by Stellar Radiation Pressure in Protoplanetary Disks
• Gravitoviscous Protoplanetary Discs with a Dust Component. IV. Disc Outer Edges, Spectral Indices, and Opacity Gaps
• Self-scattering on large, porous grains in protoplanetary disks with dust settling
• Constraints on PDS 70 b and c from the dust continuum emission of the circumplanetary discs considering in situ dust evolution
• The influence of dust grain porosity on the analysis of debris disc observations
• Global Modeling of Nebulae With Particle Growth, Drift, and Evaporation Fronts. II. The Influence of Porosity on Solids Evolution
• Relating grain size distributions in circumstellar discs to the spectral index at millimetre wavelengths
• Cloud and Haze Parameterization in Atmospheric Retrievals: Insights from Titan's Cassini Data and JWST Observations of Hot Jupiters
• 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
• Scattering polarization of 3-$\mu$m water-ice feature by large icy grains
• Evolution of dust grain size distribution and grain porosity in galaxies
• Ejection of Chondrules from Fluffy Matrices
• Multi-frequency analysis of the ALMA and VLA high resolution continuum observations of the substructured disc around CI Tau. Preference for sub-mm-sized low-porosity amorphous carbon grains
• Super-Earth formation in systems with cold giants
• Using planet migration and dust drift to weigh protoplanetary discs
• Nonlinear Outcome of Coagulation Instability in Protoplanetary Disks I: First Numerical Study of Accelerated Dust Growth and Dust Concentration at Outer Radii
• 94 Ceti: a triple star with a planet and dust disc
• Dust Production Rates in the Fomalhaut Debris Disk from SOFIA/FORCAST Mid-infrared Imaging
• The evolution of the flux-size relationship in protoplanetary discs by viscous evolution and radial pebble drift
• ALMA 873 $\mu$m Polarization Observations of the PDS~70 Disk
• From small dust to micron-sized aggregates: the influence of structure and composition on the dust optical properties
• Observed cosmic evolution of galaxy dust properties with metallicity and tensions with models
• Revealing magnetic field structure at the surfaces of protoplanetary disks via near-infrared circular polarization
• What is the amount of baryonic dark matter in galaxies?