The Colors of Comet Hyakutake

About This Image

The colors of Comet Hyakutake are caused by the action of sunlight on the dust and gas produced by the warming nucleus. The microscopic dust particles reflect sunlight while the sun's ultraviolet radiation excites and ionizes the gas molecules causing them to glow or fluoresce in a range of visible colors. This enhanced color picture reveals subtle color changes across the cometary coma and a faint multicolored tail. It was made on the night of March 18-19 by combining separate green, red, and blue photographs, each about a 15 minute exposure. Some of the color features in the tail may well represent real changes in its structure from one exposure to the next. The colored star trails, created as the Anglo-Australian Observatory's UK Schmidt Telescope tracked the rapidly moving comet, indicate the order of the separate exposures. The cometary hues revealed here can not be seen directly due to the human eye's lack of color vision at the low light levels involved. Latest Comet Hyakutake images: JPL, Fayetteville Observer-Times, NASA's Night of the Comet, ICSTARS, Crni Vrh Obs., Cent. Mich U.