Distribution Of Dust Clouds Research Articles

Experimental Investigation on Dust Vertical Coagulation Process in an Ethylene RF Discharge Plasma

The characteristics of dust coagulation process in gravitational direction are investigated in an ethylene RF (radio frequency) discharge plasma system. The experiment shows that dust particles can aggregate into the huge fractal structure (centimeter scale). The coagulation process is mainly characterized by the scattering laser intensity, the distribution of dust clouds, and the fractal dimension. In this experiment, the rotational characteristics of the huge fractal structure can be observed and investigated by the oscillation of the scattering spectrum. These results provide an experimental basis for the investigation of dust coagulations.

The Distribution of Dust Clouds in the Interstellar Medium

view Abstract Citations (10) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Distribution of Dust Clouds in the Interstellar Medium Dring, Andrew R. ; Murthy, Jayant ; Henry, R. C. ; Walker, H. J. Abstract Murthy, Walker, & Henry (1992) examined 745 O, B, F and G stars on the IRAS Skyflux plates in a search for dust clouds that are heated by the stars and found 123 clouds near 106 stars by detection of excess 60 microns emission. We have reanalyzed their sample using the Infrared Sky Survey Atlas (ISSA) data and found 194 clouds near 138 stars. We find a filling factor of (0.02 1 0.01) for dust of density greater than ∼3.0 H atoms cm-3 to which we are complete. We were able to find a good model fit to the data set with these parameters for the dust clouds: filling factor = 0.085±003 scale height z = 250±100 pc, radius power-law exponent α = -4.26±0.25, and density power-law exponent β = -1.15±0.1, where the filling factor includes material in the density range 0.01-100 H atoms cm-3; however, there is evidence to suggest that the region probed by these stars is a special environment. We also find significantly lower dust densities near O stars than near B stars. Publication: The Astrophysical Journal Pub Date: February 1996 DOI: 10.1086/176771 Bibcode: 1996ApJ...457..764D Keywords: ISM: DUST; EXTINCTION; ISM: CLOUDS; ISM: REFLECTION NEBULAE full text sources ADS | data products SIMBAD (100)

Surface distribution of dark clouds in M31 absorption gradient along the major axis, I

The distribution of dust clouds in M31 was studied based on a photocopy of this galaxy taken from Hubble'sAtlas. The picture was divided into strips starting from the center of the galaxy on both sides along the major and the minor axis, respectively. The number of dark clouds per square kiloparsec was estimated as a function of the distance from the center of the galaxy along the major axis. If we assume the validity of the standard cloud model in M31, the filling factor introduced by the model was found to vary with distance from the center. It was found furthermore, that the filling factor introduced by the model may be an upper limit. The counts of dark clouds indicate a periodical change in the absorption gradient along the major axis with a very slight systematic variation assumed by the exponential part of the representation.