English
Related papers

Related papers: Polarimetric studies of comet Halley

200 papers

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…

Earth and Planetary Astrophysics · Physics 2017-07-26 Akimasa Kataoka , Takashi Tsukagoshi , Adriana Pohl , Takayuki Muto , Hiroshi Nagai , Ian W. Stephens , Kohji Tomisaka , Munetake Momose

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…

Earth and Planetary Astrophysics · Physics 2016-03-23 Akimasa Kataoka , Takayuki Muto , Munetake Momose , Takashi Tsukagoshi , Cornelis P Dullemond

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…

Observations of interstellar extinction and polarization indicate that the interstellar medium consists of aligned non-spherical dust grains which show variation in the interstellar extinction curve for wavelengths ranging from NIR to UV.…

Astrophysics · Physics 2009-09-15 Ranjan Gupta , Tadashi Mukai , D. B. Vaidya , Asoke K. Sen , Yasuhiko Okada

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…

Dust particle sizes constrained from dust continuum and polarization observations by radio interferometry are inconsistent by at least an order of magnitude. Motivated by porous dust observed in small Solar System bodies (e.g., from the…

Earth and Planetary Astrophysics · Physics 2023-08-16 Shangjia Zhang , Zhaohuan Zhu , Takahiro Ueda , Akimasa Kataoka , Anibal Sierra , Carlos Carrasco-González , Enrique Macías

A previous study (Paper I) investigated the polarization properties of a variety of simple convex grain shapes, some of which were found to be consistent with the observed polarization properties of interstellar dust from far-ultraviolet to…

Astrophysics of Galaxies · Physics 2025-04-07 B. T. Draine

The understanding of (sub-)millimetre polarisation has made a leap forward since high-resolution imaging with ALMA came available. Amongst other effects, self-scattering (i.e., scattering of thermal dust emission on other grains) is thought…

Solar and Stellar Astrophysics · Physics 2020-07-01 Florian Kirchschlager , Gesa H. -M. Bertrang

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…

Comet NEAT C/2001 Q4 was observed for linear polarization using the optical polarimeter mounted at the 1.2m telescope at Mt. Abu Observatory, during the months of May and June 2004. Observations were conducted through the International…

Earth and Planetary Astrophysics · Physics 2015-05-13 S. Ganesh , U. C. Joshi , K. S. Baliyan

In this work, we introduce a comet dust model that incorporates multiple dust morphologies along with inhomogeneous mixture of silicate minerals and carbonaceous materials under power-law size distribution, to replicate the standard…

Earth and Planetary Astrophysics · Physics 2020-12-03 Prithish Halder , Shashikiran Ganesh

The optical properties of the second generation dust that we observe in debris disks remain quite elusive, whether it is the absorption efficiencies at millimeter wavelengths or the (un)polarized phase function at near-infrared wavelengths.…

Earth and Planetary Astrophysics · Physics 2022-08-24 Johan Olofsson , Philippe Thébault , Grant M. Kennedy , Amelia Bayo

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…

The debris disc around HD 172555 was recently imaged in near-infrared polarised scattered light by the Very Large Telescope's Spectro-Polarimetric High-contrast Exoplanet REsearch instrument. Here we present optical aperture polarisation…

Earth and Planetary Astrophysics · Physics 2020-11-30 Jonathan P. Marshall , Daniel V. Cotton , Peter Scicluna , Jeremy Bailey , Lucyna Kedziora-Chudczer , Kimberly Bott

Our aim is to study the polarization of thermal dust emission to see if the alignment of grain by radiative torques could explain the observed relation between the degree of polarization and the intensity in dense cores. Predictions are…

Astrophysics · Physics 2009-11-11 V. -M. Pelkonen , M. Juvela , P. Padoan

We present experimental phase function and degree of linear polarization curves for seven samples of cometary dust analogues namely: ground pieces of Allende, DaG521, FRO95002 and FRO99040 meteorites, Mg-rich olivine and pyroxene, and a…

The dependence of polarization fraction $p$ on total intensity $I$ in polarized submillimeter emission measurements is typically parameterized as $p\propto I^{-\alpha}$ $(\alpha \leq 1)$, and used to infer dust grain alignment efficiency in…

We present the polarization observations toward the circumstellar disk around HD 142527 by using Atacama Large Millimeter/submillimeter Array (ALMA) at the frequency of 343 GHz. The beam size is $0.51 " \times 0.44 "$, which corresponds to…

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…

Solar and Stellar Astrophysics · Physics 2014-09-05 F. Kirchschlager , S. Wolf