Steps toward interstellar silicate mineralogy
نویسندگان
چکیده
منابع مشابه
Steps toward interstellar silicate mineralogy IV. The crystalline revolution
Midand far-infrared spectra gained by the Short Wavelength Spectrometer (SWS) of the Infrared Space Observatory (ISO) satellite have provided striking evidence for the presence of crystalline silicates in comets, circumstellar envelopes around young stars and, most of all, evolved stars and planetary nebulae. Since optical properties of astrophysically relevant crystalline silicates are lacking...
متن کاملSteps toward interstellar silicate mineralogy V. Thermal evolution of amorphous magnesium silicates and silica
The thermally induced amorphous-to-crystalline transition has been studied for bulk sheets and micrometre-sized particles of magnesium silicate glass (MgSiO3), nanometresized amorphous magnesium silicate (MgSiO3 and Mg2SiO4 smokes) and amorphous silica particles (SiO2). Silicate glass was produced by the shock-quenching of melts. Samples of nanometre-sized smoke particles have been obtained by ...
متن کاملSteps toward interstellar silicate mineralogy III. The role of aluminium in circumstellar amorphous silicates
It is a well-known fact that the spectra of oxygen-rich circumstellar dust envelopes around evolved stars show great diversity, especially in the 10 μm silicate band profiles, but also in the longer infrared wavelength range covered by ISO. This supports earlier conclusions that the concept of a universal cosmic silicate is inadequate and that it is reasonable to consider a wider variety of pos...
متن کاملOn the Crystallinity of Silicate Dust in the Interstellar Medium
An accurate knowledge of the mineralogy (chemical composition and crystal structure) of the silicate dust in the interstellar medium (ISM) is crucial for understanding its origin in evolved stars, the physical and chemical processing in the ISM, and its subsequent incorporation into protostellar nebulae, protoplanetary disks and cometary nuclei where it is subjected to further processing. While...
متن کاملEnergetic Processing of Interstellar Silicate Grains by Cosmic Rays
While a significant fraction of silicate dust in stellar winds has a crystalline structure, in the interstellar medium nearly all of it is amorphous. One possible explanation for this observation is the amorphization of crystalline silicates by relatively ‘‘low’’ energy, heavy-ion cosmic rays. Here we present the results of multiple laboratory experiments showing that single-crystal synthetic f...
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: Astronomy & Astrophysics
سال: 2001
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20011196