منابع مشابه
Interstellar Dust Grains
This review surveys the observed properties of interstellar dust grains: the wavelength-dependent extinction of starlight, including absorption features, from UV to infrared; optical luminescence; infrared emission; microwave emission; optical, UV, and X-ray scattering by dust; and polarization of starlight and of infrared emission. The relationship between presolar grains in meteorites and the...
متن کاملTemperature fluctuations of interstellar dust grains
The temperatures of interstellar dust grains are analyzed using stochastic simulations, taking into account the grain composition and size and the discreteness of the photon flux. Grains of radii smaller than about 0.02 μm are found to exhibit large temperature fluctuations with narrow spikes following the absorption of UV photons. The temperatures of such grains may rise by a few × 10 K for ve...
متن کاملConstraining the Porosities of Interstellar Dust Grains
We present theoretical calculations of the X-ray scattering properties of porous grain aggregates with olivine monomers. The small and large angle scattering properties of these aggregates are governed by the global structure and substructure of the grain, respectively. We construct two diagnostics, RX and TX, based on the optical and X-ray properties of the aggregates, and apply them to a Chan...
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 کاملOptical , UV , and X - Ray Scattering by Interstellar Dust Grains
Scattering and absorption properties at optical, ultraviolet, and X-ray wavelengths are calculated for an interstellar dust model consisting of carbonaceous grains and amorphous silicate grains. The widely-used Henyey-Greenstein phase function provides a good approximation for the scattering phase function at wavelengths between ∼0.4 and 1µm, but fails to fit the calculated phase functions at s...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Nature
سال: 1997
ISSN: 0028-0836,1476-4687
DOI: 10.1038/387248a0