Dust tail

Dust tail

. This photograph of Comet West (1975 VI) shows a broad, curved, pearly-hued dust tail. Because dust particles scatter sunlight, the dust tail has a slightly yellow color. It has a delicate lacy structure, created by countless dust particles shed from the comet nucleus over many days. A cometís ion tail absorbs sunlight and re-emits it by the fluorescence process. Its visible radiation is dominated by the fluorescence of ionized carbon monoxide, which gives the ion tails a blue color. Dennis DiCiccio took this photograph at 4:30 a.m. on 8 March 1976 from Duxbury Beach Massachusetts with a 2-minute exposure and at f/2. (Courtesy of Dennis DiCiccio, Sky and Telescope.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University