منابع مشابه
Interstellar extinction by porous grains
Interstellar extinction curve E(λ-V)/E(B-V) vs 1/λ is evaluated in the spectral range 3.4 μm and 0.1 μm using the extinction efficiencies of the porous silicate and graphite grains. The extinction efficiencies of the porous silicate and graphite grains are computed using the discrete dipole approximation (DDA). The model curves are compared with the average observed interstellar extinction curv...
متن کاملInterstellar Extinction by Spheroidal Dust Grains
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. To model the extinction and polarization, one cannot use the conventional Mie theory which assumes the grains as solid spheres. We have used a T-matrix based ...
متن کاملInterstellar extinction by fractal polycrystalline graphite clusters ?
Interstellar extinction by fractal polycrystalline graphite clusters?, Andersen et al. Abstract 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 observed interstellar extinction peak at ∼ 4.6 µm, we have calculate...
متن کاملTwo Lines of Sight with Exceedingly Anomalous Uv Interstellar Extinction
Low resolution IUE data obtained towards HD 62542, a B5 V star in a line of sight associated with a dark cloud in the Gum Nebula region near & Pup (OS Iaf) and y Vel (WC8 + 09 I), yields an extinction curve with an extremely broad and weak W extinction bump and the highest far-UV extinction yet obseaved in the Milky Way, reaching a value of E(1200-V)/E(B-v)p115. The weak bump is very similar to...
متن کاملModelling interstellar extinction and polarization with spheroidal grains
We calculate the wavelength dependence of the ratio of the linear polarization degree to extinction (polarizing efficiency) P(λ)/A(λ) from the ultraviolet to near-infrared. The prolate and oblate particles with aspect ratios from a/b = 1.1 up to 10 are assumed to be rotating and partially aligned with the mechanism of paramagnetic relaxation (Davis– Greenstein). Size/shape/orientation effects a...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1970
ISSN: 0074-1809
DOI: 10.1017/s0074180900101780