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In a series of two recent papers, the frequency and size distribution dependence of extinction spectra for astronomical silicate and graphite grains was analyzed by us in the context of MRN type interstellar dust models. These grains were…

Astrophysics of Galaxies · Physics 2012-02-24 Ashim K. Roy , Subodh K. Sharma , Ranjan Gupta , Pritesh Ranadive

We apply the time evolution of grain size distributions by accretion and coagulation found in our previous work to the modelling of the wavelength dependence of interstellar linear polarization. We especially focus on the parameters of the…

Astrophysics of Galaxies · Physics 2015-06-22 Nikolai V. Voshchinnikov , Hiroyuki Hirashita

We calculate the ionization fraction of protostellar alpha disks, taking into account vertical temperature structure, and the possible presence of trace metal atoms. Both thermal and X-ray ionization are considered. Previous investigations…

Astrophysics · Physics 2008-11-26 S. Fromang , C. Terquem , S. A. Balbus

The distance to the stars is a fundamental parameter, which is determined via two primary methods - parallax and luminosity. While the parallax is a direct trigonometric method, the luminosity distance is usually influenced by interstellar…

Astrophysics of Galaxies · Physics 2024-12-30 Ralf Siebenmorgen , Frank Heymann , Rolf Chini

We study the extinction properties of highly porous BCCA dust aggregates in a wide range of complex refractive indices ($1.4 \le n \le 2.0$, $0.001 \le k \le 1.0$) and wavelength ($0.11\mu m \le \lambda \le 3.4\mu m$). An attempt has been…

Earth and Planetary Astrophysics · Physics 2017-11-08 Tanuj Kumar Dhar , Himadri Sekhar Das

The polarization of starlight and thermal dust emission, resulting from non-spherical grains aligned with the interstellar magnetic field (B-field), act as a powerful tool to trace the B-field morphologies and strengths in molecular clouds…

Astrophysics of Galaxies · Physics 2026-05-26 Saikhom Pravash

We determine the slope of the near infrared extinction power law (A$_{\lambda} \propto \lambda^{-\alpha}$) for 8 regions of the Galaxy between l$\sim27^{\circ}$ and $\sim100^{\circ}$. UKIDSS Galactic Plane Survey data are compared, in…

Astrophysics of Galaxies · Physics 2015-05-13 J. J. Stead , M. G. Hoare

We present optical and near-infrared stellar polarization observations toward the dark filamentary clouds associated with IC5146. The data allow us to investigate the dust properties (this paper) and the magnetic field structure (Paper II).…

Astrophysics of Galaxies · Physics 2017-11-15 Jia-Wei Wang , Shih-Ping Lai , C. Eswaraiah , Dan P. Clemens , Wen-Ping Chen , A. K. Pandey

Polarimetry is one of the keys to enhanced direct imaging of exoplanets. Not only does it deliver a differential observable providing extra contrast, but when coupled with spectroscopy, it also reveals valuable information on the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 Guillaume Schworer , Peter G. Tuthill

Scattering and absorption properties at optical and ultraviolet wavelengths are calculated for an interstellar dust model consisting of carbonaceous grains and amorphous silicate grains. Polarization as a function of scattering angle is…

Astrophysics · Physics 2011-05-05 B. T. Draine

The properties of polarization in scattered light by aligned ellipsoidal grains are investigated with the Fredholm integral equation method (FIM) and the T-matrix method (Tmat), and the results are applied to the observed circular…

Astrophysics of Galaxies · Physics 2010-01-15 Masafumi Matsumura , Pierre Bastien

The extinction law from ultraviolet (UV) to infrared (IR) (0.2-24 $\mu$m) is determined by relying on the blue-edge method and color excess ratios for some nearby molecular clouds, from low mass star forming region to massive star forming…

Astrophysics of Galaxies · Physics 2024-10-04 Zhetai Cao , Biwei Jiang , Shu Wang , Jun Li

We present a new method for using the observed starlight polarization and polarized submm emission to constrain the shapes and porosities of interstellar grains. We present the modified picket fence approximation (MPFA), and verify that it…

Astrophysics of Galaxies · Physics 2021-10-04 B. T. Draine , Brandon S. Hensley

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…

Solar and Stellar Astrophysics · Physics 2020-08-26 Robert Brunngräber , Sebastian Wolf

We report measurements of the temperature $T $ dependence of the linear polarization $\langle P\rangle $ of the thermal radiation emitted by thin, incandescent tungsten wires. We investigated an interval ranging from a little above room…

Optics · Physics 2015-02-25 A. F. Borghesani , G. Carugno

We present a new model of interstellar dust in which large grains are a single composite material, ``astrodust,'' and nanoparticle-sized grains come in distinct varieties including polycyclic aromatic hydrocarbons (PAHs). We argue that a…

Astrophysics of Galaxies · Physics 2023-06-07 Brandon S. Hensley , B. T. Draine

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…

Earth and Planetary Astrophysics · Physics 2019-07-10 Florian Kirchschlager , Gesa H. -M. Bertrang , Mario Flock

Polarization is a unique tool to study the properties of dust grains of protoplanetary disks and detail the initial conditions of planet formation. Polarization around HL Tau was previously imaged using the Atacama Large…

Near- to mid-infrared period-magnitude relations and also the period-bolometric luminosity relation of OGLE-III Mira-like variables in the LMC are derived. The relations have a kink, and the period at which the break occurs is…

Solar and Stellar Astrophysics · Physics 2015-05-20 Y. Ita , N. Matsunaga

For more than 5000 stars with accurate parallaxes from the Hipparcos and Gaia DR1 Tycho-Gaia astrometric solution (TGAS), Tycho-2 photometry, interstellar polarization from eight catalogues and interstellar extinction from eight 3D maps the…

Astrophysics of Galaxies · Physics 2017-07-26 George Gontcharov