These images were used to produce the combined false-color enhanced images immediately above. These six images of Comet Hale-Bopp have been processed so the gas and dust in the comet can be investigated separately. The cyanogen gas is re-emitting light absorbed from the sun. This process is known as fluorescence and is more efficient closer to the sun. In the corresponding series of images shown in the bottom row, sunlight scattered from dust particles is shown.
North is to the top and east is to the right.
The sun is shining from south of southeast, or slightly left of bottom in these pictures. Examining the structure of these gas and dust images of the inner coma you'll notice a dominant, bright feature in each picture. This is a strong jet which repeatably comes into sunlight as the nucleus rotates. The sunlight activates the jet and so CN is most apparent on the sunward side of the comet nucleus. The presence of CN all around the coma is possibly caused by the release of CN molecules from dust grains in the coma, in addition to CN emission released directly from gaseous molecules at the surface of the nucleus.