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911.
This paper reports laboratory investigations on the absorption spectrum of SiC particles in the 10 μm region. The particles had a mean diameter of 0.31 μm. Our experimental results indicate that a large part of the infrared excess observed in carbon stars may be caused by SiC. 相似文献
912.
913.
J. A. Docobo V. S. Tamazian N. D. Melikian M. H. Eritsian A. A. Karapetian 《Astrophysics》2000,43(2):162-169
The results of photometric and polarimetric observations of the star Μ Cep at Byurakan Observatory are presented. Some interesting
correlations between the parameters of the star’s brightness variation and the degree of polarization of the light are obtained.
It is suggested that the recorded rapid changes in the degree of polarization may result from Μ Cep being a double star.
Translated from Astrofizika, Vol. 43, No. 2, pp. 219-228, April–June, 2000. 相似文献
914.
915.
916.
917.
Europa is bombarded by intense radiation that erodes the surface, launching molecules into a thin “atmosphere” representative of surface composition. In addition to atoms and molecules created in the mostly water ice surface such as H2O, O2, H2, the atmosphere is known to have species representative of trace surface materials. These trace species are carried off with the 10-104 H2O molecules ejected by each energetic heavy ion, a process we have simulated using molecular dynamics. Using the results of those simulations, we found that a neutral mass spectrometer orbiting ∼100 km above the surface could detect species with surface concentrations above ∼0.03%. We have also modeled the atmospheric spatial structure of the volatile species CO2 and SO2 under a variety of assumptions. Detections of these species with moderate time and space resolution would allow us to constrain surface composition, chemistry and to study space weathering processes. 相似文献
918.
919.
J. Dorschner 《Astrophysics and Space Science》1982,81(1-2):323-328
In this paper, grain-grain collisions, which were recently suggested by Biermann and Harwit (1980) to occur in cool circumstellar envelopes and to be responsible for the interstellar grain size spectrum, are investigated. On the basis of the author's fragmentation theory, it is shown that in the result of such collisions size distributions of the typen(a) a
–p
arise. In the steady-state case the exponentp ranges from 3.4 to 3.7. This result matches well with grain size spectra derived from the interstellar extinction curve. 相似文献
920.
The mean width and distribution of penumbral filaments of a sunspot have been estimated, using white light photographs obtained with a vacuum, Newtonian type, telescope. Three areas corresponding to the penumbra of a sunspot have been analysed. Data were collected during the solar eclipse of June 1973. The photometric profiles of the Moon limb over the photosphere have been analysed to obtain useful information on both, atmospheric and instrumental perturbation on each exposure. The mean value of the width of penumbral filaments is 0.37 arc sec.Now at INTA-Villafranca, S.T.S., P.O. Box 54065, Madrid, Spain. 相似文献