相关论文: Opacity of fluffy dust aggregates

In this paper we analyze new observations from ALMA and VLA, at a high angular resolution corresponding to 5 - 8 au, of the protoplanetary disk around HD 163296 to determine the dust spatial distribution and grain properties. We fit the…

Context: In protoplanetary discs, micron-sized dust grows to form millimetre- to centimetre-sized pebbles but encounters several barriers during its evolution. Collisional fragmentation and radial drift impede further dust growth to…

We aim at determining the spatial distribution of the gas and dust in star-forming regions and address their relative abundances in quantitative terms. We also examine the dust opacity exponent beta for spatial and/or temporal variations.…

In order to explain grain growth to mm sized particles and their retention in outer regions of protoplanetary disks, as it is observed at sub-mm and mm wavelengths, we investigate if strong inhomogeneities in the gas density profiles can…

The charge on an aggregate immersed in a plasma environment distributes itself over the aggregate's surface; this can be approximated theoretically by assuming a multipole distribution. The dipole-dipole (or higher order) charge…

Large-scale vortices in protoplanetary disks are thought to form and survive for long periods of time. Hence, they can significantly change the global disk evolution and particularly the distribution of the solid particles embedded in the…

We have derived the albedo ($a$) and phase function asymmetry factor ($g$) of interstellar dust grains at 1100 \AA ~ using archival {\it Voyager} observations of diffuse radiation in Ophiuchus. We have found that the grains are highly…

We are motivated by the recent measurements of dust opacity indices beta around young stellar objects (YSOs), which suggest that efficient grain growth may have occurred earlier than the Class I stage. The present work makes use of abundant…

Multi-wavelength dust continuum observations of protoplanetary disks are essential for accurately measuring two key ingredients of planets formation theories: the dust mass and grain size. Unfortunately, they are also extremely…

Early dust grain growth in protostellar envelopes infalling on young discs has been suggested in recent studies, supporting the hypothesis that dust particles start to agglomerate already during the Class 0/I phase of young stellar objects…

The thermal emission of dust is one of the most important tracers of the interstellar medium: multi-wavelength photometry in the far-infrared (FIR) and submillimeter (submm) can be fitted with a model, providing estimates of the dust mass.…

We aim at understanding the formation of cloud layers in quasi-static substellar atmospheres. The time-dependent description presented in (Helling & Woitke 2006) is a kinetic model describing nucleation, growth and evaporation. It is…

We study the fraction of stellar radiation absorbed by dust, f_abs, in 814 galaxies of different morphological types. The targets constitute the vast majority (93%) of the DustPedia sample, including almost all large (optical diameter…

Recent laboratory experiments have revealed that destructive collisions of icy dust particles may occur at much lower velocities than previously believed. These low fragmentation velocities push down the maximum grain size in collisional…

Dust grains in protoplanetary disks are the building blocks of planets. Investigating the dust composition and size, and their variation over time, is crucial for understanding the planet formation process. The PDS 70 disk is so far the…

Planet formation models rely on knowledge of the physical conditions and evolutionary processes in protoplanetary disks, in particular the grain size distribution and dust growth timescales. In theoretical models, several barriers exist…

Context: In protoplanetary disks, dust grains coagulate with each other and grow to form aggregates. As these aggregates grow by coagulation, their filling factor \phi decreases down to \phi << 1. However, comets, the remnants of these…

The Sun and >15 percent of nearby stars are surrounded by dusty debris disks that must be collisionally replenished by asteroids and comets, as the dust would otherwise be depleted on <10 Myr timescales (ref. 1). Theoretical studies show…

We present a detailed multi-wavelength characterization of the multi-ring disk of HD 169142. We report new ALMA observations at 3 mm and analyze them together with archival 0.89 and 1.3 mm data. Our observations resolve three out of the…

Study of cosmic dust and planetary aerosols indicate that some of them contain a large number of aggregates of the size that significantly exceeds the wavelengths of the visible light. In some cases such large aggregates may dominate in…