interstellar extinction

interstellar extinction

The reduction in brightness, i.e. the extinction, of light (and other radiation) from stars as a result of absorption and scattering of the radiation by interstellar dust. Although dust makes up only a small proportion of the interstellar medium, its effect on starlight is considerable. The amount of extinction, usually measured in magnitudes, depends on the direction of observation. It is a maximum (about one magnitude per kiloparsec distance for visible wavelengths) toward the center of the Galaxy, where the density and extent of the dust is greatest. The extinction varies inversely with wavelength. Red light is thus less affected than blue light so that starlight appears reddened when observed through a dust cloud; this interstellar reddening can also be used to map the presence of dust in the Galaxy. Radio and infrared waves with their longer wavelengths can pass through the interstellar medium with ease compared with optical wavelengths. The presence of obscuring matter between the stars was first conclusively demonstrated by Robert Trumpler in 1930.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

interstellar extinction

[¦in·tər¦stel·ər ik′stiŋk·shən]
(astronomy)
The dimming of light from stars due to its absorption and scattering by dust grains in the interstellar medium.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
He determined that the interstellar extinction in magnitudes is a factor of 1.22 times greater in the blue (i.e.
In fact, the cluster is 6,700 light-years away and dimmed 1.6 magnitudes by interstellar extinction. My 10-inch reflector at 213x shows many faint to very faint stars over a 31/2' haze with a curve of three brighter stars off its southern side.
Since this nebula is 38[degrees] from the galactic equator, we do not anticipate that interstellar extinction and reddening will change the magnitudes significantly.
If it is assumed that interstellar extinction is negligible then the surface brightness and absolute magnitude of NGC 6210 can be determined.
The color is undoubtedly effected by interstellar extinction (Kaler et al.
Interstellar extinction dims it an estimated 1.6 magnitudes.