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A(B) and A(V) are the total extinction at the B and V filter bands. Another measure used in the literature is the absolute extinction A(λ)/A(V) at wavelength λ, comparing the total extinction at that wavelength to that at the V band. R(V) is known to be correlated with the average size of the dust grains causing the extinction.
Cosmic dust – also called extraterrestrial dust, space dust, or star dust – is dust that occurs in outer space or has fallen onto Earth. [ 1 ] [ 2 ] Most cosmic dust particles measure between a few molecules and 0.1 mm (100 μm ), such as micrometeoroids (<30 μm) and meteoroids (>30 μm). [ 3 ]
In Saturn's magnetosphere the active moon Enceladus at 4 (= 6.0 × 10 4 km is Saturn's radius) is a source of oxygen and water ions at a density of 10 9 m −3 and an energy 5 eV. Dust particles are charged to a surface potential of -1 and -2 V. Outside 4 the ion energy increases to 100 eV and the resulting surface potential rises to +5 V. [166 ...
The Zone of Avoidance (ZOA, ZoA), or Zone of Galactic Obscuration (ZGO), [1] [2] is the area of the sky that is obscured by the Milky Way. [ 3 ] The Zone of Avoidance was originally called the Zone of Few Nebulae in an 1878 paper by English astronomer Richard Proctor that referred to the distribution of " nebulae " in John Herschel 's General ...
Dust grains are heated via this radiation and can transfer thermal energy during collisions with the gas. A measure of efficiency in the heating is given by the accommodation coefficient: α = T 2 − T T d − T {\displaystyle \alpha ={\frac {T_{2}-T}{T_{d}-T}}} where T is the gas temperature, T d the dust temperature, and T 2 the post ...
A comparison of this value with the apparent magnitude allows the approximate distance to be determined, after correcting for interstellar extinction of the luminosity because of gas and dust. In a gravitationally-bound star cluster such as the Hyades, the stars formed at approximately the same age and lie at the same distance. This allows ...
The Sun's passage through the higher density spiral arms of the galaxy, rather than its passage through the plane of the galaxy, could hypothetically coincide with mass extinction on Earth. [5] However, a reanalysis of the effects of the Sun's transit through the spiral structure based on CO data has failed to find a correlation.
The superbubble Henize 70, also known as N70 or DEM301, in the Large Magellanic Cloud [1]. In astronomy a superbubble or supershell is a cavity which is hundreds of light years across and is populated with hot (10 6 K) gas atoms, less dense than the surrounding interstellar medium, blown against that medium and carved out by multiple supernovae and stellar winds.