Effect of dust size and structure on scattered light images of protoplanetary discs

Abstract

We study scattered light properties of protoplanetary discs at near-infrared wavelengths for various dust size and structure by performing radiative transfer simulations. We show that different dust structures might be probed by measuring disk polarisation fraction as long as the dust radius is larger than the wavelength. When the radius is larger than the wavelength, disc scattered light will be highly polarised for highly porous dust aggregates, whereas more compact dust structure tends to show low polarisation fraction. Next, roles of monomer radius and fractal dimension for scattered light colours are studied. We find that, outside the Rayleigh regime, as fractal dimension or monomer radius increases, colours of the effective albedo at near-infrared wavelengths vary from blue to red. Our results imply that discs showing grey or slightly blue colours and high polarisation fraction in near-infrared wavelengths might be explained by the presence of large porous aggregates containing sub-microns sized monomers.

Accepted for publication in MNRAS, 18 pages, 19 figures

References in corpus (7)

• Dust coagulation in protoplanetary disks: porosity matters
• 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
• Scattered light mapping of protoplanetary disks
• Effect of dust grain porosity on the appearance of protoplanetary disks
• Experimental phase functions of mm-sized cosmic dust grains
• Low-velocity collision behaviour of clusters composed of sub-mm sized dust aggregates

Cited by in corpus (2)

• Nonsticky Ice at the Origin of the Uniformly Polarized Submillimeter Emission from the HL Tau Disk
• NaCo polarimetric observations of Sz 91 transitional disk: a remarkable case of dust filtering