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Related papers: Interstellar Grains: Effect of Inclusions on Extin…

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The composite grain is made up of a host silicate spheroid and graphite inclusions. The extinction efficiencies of the composite spheroidal grains for three axial ratios are computed using the discrete dipole approximation (DDA). The…

Astrophysics · Physics 2009-06-23 D. B. Vaidya , Ranjan Gupta , T. P. Snow

We study the extinction properties of the composite dust grains, consisting of host silicate spheroids and graphite as inclusions, using discrete dipole approximation (DDA). We calculate the extinction cross sections of the composite grains…

Solar and Stellar Astrophysics · Physics 2015-06-17 Nisha Katyal , Ranjan Gupta , D B Vaidya

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

In this paper we study the effects of inclusions and porosities on the emission properties of silicate grains and compare the model curves with the observed infrared emission from circumstellar dust. We calculate the absorption efficiency…

Solar and Stellar Astrophysics · Physics 2015-03-17 D. B. Vaidya , Ranjan Gupta

We extend and investigate the spheroidal model of interstellar dust grains used to simultaneously interpret the observed interstellar extinction and polarization curves. We compare our model with similar models recently suggested by other…

Astrophysics of Galaxies · Physics 2015-05-14 H. K. Das , N. V. Voshchinnikov , V. B. Il'in

Interstellar dust is a major foreground contaminant for many observations and a key component in the chemistry of the interstellar medium, yet its properties remain highly uncertain. Using low-resolution spectra, we accurately measure the…

Astrophysics of Galaxies · Physics 2024-07-23 Xiangyu Zhang , Gregory Green

The review contains an analysis of the observed and model curves of the interstellar extinction and polarization. The observations mainly give information on dust in diffuse and translucent interstellar clouds. The features of various dust…

Astrophysics of Galaxies · Physics 2015-06-05 N. V. Voshchinnikov

The wavelength dependences of interstellar extinction and polarization, supplemented by observed elemental abundances and the spectrum of infrared emission from dust heated by starlight, strongly constrain dust models. One dust model that…

Astrophysics of Galaxies · Physics 2009-03-11 B. T. Draine

Certain dust particles in space are expected to appear as clusters of individual grains. The morphology of these clusters could be fractal or compact. To determine how these structural features would affect the interpretation of the…

Astrophysics · Physics 2007-05-23 A. C. Andersen , J. A. Sotelo , V. N. Pustovit , G. A. Niklasson

We calculate the absorption efficiency of the composite grains, made up of host silicate spheroids and inclusions of ices/graphites/or voids, in the spectral region $7.0-14.0\mu$m The absorption efficiencies of the composite spheroidal…

Astrophysics of Galaxies · Physics 2009-04-03 Deepak B. Vaidya , Ranjan Gupta

It is generally agreed that interstellar dust grains consist of two main components, namely, silicates and graphites. Some models, like MRN model, assume these grains to be homogeneous spheres following a power law size distribution. This…

Astrophysics of Galaxies · Physics 2009-03-30 Ashim K. Roy , Subodh K. Sharma , Ranjan Gupta

We present a model for the diffuse interstellar dust that explains the observed wavelength-dependence of extinction, emission, linear and circular polarisation of light. The model is set-up with a small number of parameters. It consists of…

Astrophysics of Galaxies · Physics 2015-06-16 R. Siebenmorgen , N. V. Voshchinnikov , S. Bagnulo

We construct a quasar extinction curve based on the blue and red composite quasar spectra of Richards et al. (2003) prepared from the SDSS survey. This extinction curve does not show any traces of the 2200 A feature characteristic of the…

Astrophysics · Physics 2009-11-10 B. Czerny , J. Li , Z. Loska , R. Szczerba

The sizes of interstellar grains are widely distributed, ranging from a few angstroms to a few micrometers. The ultraviolet (UV) and optical extinction constrains the dust in the size range of a couple hundredth micrometers to several…

Astrophysics of Galaxies · Physics 2015-09-23 Shu Wang , Aigen Li , B. W. Jiang

Interstellar dust plays a central role in shaping the detailed structure of the interstellar medium, thus strongly influencing star formation and galaxy evolution. Dust extinction provides one of the main pillars of our understanding of…

Context: Dust grains are key components of the interstellar medium and play a central role in star formation, acting as catalysts for chemical reactions and as building blocks of planets. Extinction curves are essential for characterizing…

Interstellar dust models are facing a "carbon crisis", so called because recent observations suggest that the abundance of carbon available for dust in the interstellar medium is less than half of the amount required to be tied up in…

Astrophysics · Physics 2016-08-30 E. Dwek

Modern data of the extinction curve from the ultraviolet to the near infrared are revisited to study the property of dust grains in the Milky Way (MW) and the Small Magellanic Cloud (SMC). We confirm that the graphite-silicate mixture of…

Astrophysics of Galaxies · Physics 2015-06-12 Takaya Nozawa , Masataka Fukugita

We calculate the absorption efficiencies of composite silicate grains with inclusions of graphite and silicon carbide in the spectral range 5--25$\rm \mu m$. We study the variation in absorption profiles with volume fractions of inclusions.…

Astrophysics of Galaxies · Physics 2016-07-22 Ranjan Gupta , Dipak B. Vaidya , Rajeshwari Dutta

How dust scatters and absorbs starlight in the interstellar medium (ISM) contains important clues about the size and composition of interstellar dust. While the ultraviolet (UV) and visible interstellar extinction is well studied and can be…

Astrophysics of Galaxies · Physics 2015-06-19 Shu Wang , Aigen Li , B. W. Jiang
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