相关论文: Self-scattering of non-spherical dust grains
Observations of protoplanetary disks (PPDs) at sub-mm wavelengths suggest that polarisation is caused by scattering of thermal radiation. Most of the dust models that are used to explain these observations have major drawbacks: They either…
Scattering of re-emitted flux is considered to be at least partially responsible for the observed polarisation in the (sub-)millimetre wavelength range of several protoplanetary disks. Although the degree of polarisation produced by…
We present a new method to constrain the grain size in protoplanetary disks with polarization observations at millimeter wavelengths. If dust grains are grown to the size comparable to the wavelengths, the dust grains are expected to have a…
Polarization at millimeter wavelengths provides a powerful diagnostic of dust grain properties in protoplanetary disks. Standard models based on solid spherical grains often struggle to reproduce the observed polarization fractions and…
Spatially resolved (sub)millimeter polarization has been detected by ALMA in an increasing number of disks around young stellar objects. The majority of the observations show polarization patterns that are consistent with self-scattering,…
The size of dust grains, $a$, is key to the physical and chemical processes in circumstellar disks, but observational constraints of grain size remain challenging. (Sub)millimeter continuum observations often show a percent-level…
Disk polarization at (sub)millimeter wavelengths is being revolutionized by ALMA observationally, but its origin remains uncertain. Dust scattering was recently recognized as a potential contributor to polarization, although its basic…
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…
The millimeter-wave polarization of the protoplanetary disk around HL Tau has been interpreted as the emission from elongated dust grains aligned with the magnetic field in the disk. However, the self-scattering of thermal dust emission may…
Multiwavelength dust continuum and polarization observations arising from self-scattering have been used to investigate grain sizes in young disks. However, the polarization by self-scattering is low in face-on optically thick disks and…
We theoretically analyze protoplanetary disks consisting of porous dust grains. In the analysis of observations of protoplanetary disks the dust phase is often assumed to consist of spherical grains, allowing one to apply the Mie scattering…
During the evolution of protoplanetary disks, dust grains start to grow, form larger particles, settle to the midplane, and rearrange the disk, mainly by the inward radial drift. Because of this, dust pebbles with an irregular shape usually…
The origin of polarized emission from protoplanetary disks is uncertain. Three mechanisms have been proposed for such polarized emission: grain alignment with magnetic fields, grain alignment with radiation gradients, and self-scattering of…
We present the first numerical radiative transfer simulation of multiple light scattering in dust configurations containing aligned non-spherical (spheroidal) dust grains. Such models are especially important if one wants to explain the…
Dust polarization at (sub)millimeter wavelengths has been observed for many protoplanetary disks. Theoretically, multiple origins potentially contribute to the polarized emission but it is still uncertain what mechanism is dominant in disk…
The mechanism for producing polarized emission from protostellar disks at (sub)millimeter wavelengths is currently uncertain. Classically, polarization is expected from non-spherical grains aligned with the magnetic field. Recently, two…
Polarized (sub)millimeter emission from dust grains in circumstellar disks was initially thought to be due to grains aligned with the magnetic field. However, higher resolution multi-wavelength observations along with improved models found…
(Sub-)Millimeter observations of the polarized emission of aligned aspherical dust grains enable us to study the magnetic fields within protoplanetary disk. However, the interpretation of these observations is complex. One must consider the…
The mechanisms causing millimeter-wave polarization in protoplanetary disks are under debate. To disentangle the polarization mechanisms, we observe the protoplanetary disk around HL Tau at 3.1 mm with the Atacama Large…
The azimuthal polarization patterns observed in some protoplanetary disks by ALMA at millimeter wavelength have raised doubts about their being produced by dust grains aligned with the magnetic field lines. These conclusions were based on…