Comet C/1995 O1 (Hale-Bopp) at the WIYN Telescope

NOAO/KPNO is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under cooperative agreement with the National Science Foundation


You are encouraged to publish these images for informational or instructional purposes. If you do, please attach the following credit: "WIYN Telescope Image provided courtesy of the WIYN Consortium, Inc. (Wisconsin, Indiana, and Yale Universities and the National Optical Astronomy Observatories) with support of the National Science Foundation.", or more concisely "Photo courtesy WIYN Consortium, Inc. and the National Science Foundation."

image image The inner coma of Comet Hale-Bopp is shown here on April 1 (left), and April 2, 1997 (right). The images have been computer processed to show structure in the distribution of the comet's gas and dust. Locations in the comet where gaseous cyanogen (CN) molecules are emitting light are shown in this false-color image as yellow-green; areas which contain reflections from dust particles are shown in bluish-white. The spiral structure apparent in these pictures results from jets of gaseous material being ejected in a stream from the comet nucleus. The rotation of the comet nucleus, approximately once every eleven hours, wraps the ejected material around the nucleus in the spiral structure shown. Notice that the areas of strong CN emission are similar, but not identical, in structure to those strong in dust reflections.

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. The strong dust features in the sunward side wash out the CN features on that side; in the side of the image that faces away from the sun, the side where the comet's tail would be seen, only CN features are seen and structure in the dust is not apparent. All energy emitted by a comet comes from the sun, either by the scattering of radiated sunlight from dust particles or from the reemission of absorbed sunlight by gas molecules, known as fluorescence. Details of the structure in these images give clues to the physical processes of CN and dust in Comet Hale-Bopp.

These images cover an area of about 100,000 km in diameter centered on the comet nucleus, an area visible to the unaided eye as the innermost, fuzzy "coma" of Hale-Bopp. The individual images used to produce these pictures are shown immediately below.

The original images were taken with the WIYN telescope on Kitt Peak near Tucson, AZ and were provided courtesy of Beatrice Mueller and Nalin Samarasinha, NOAO. The individual images were combined and color enhanced by Nigel Sharp (NOAO).


image These four images taken at the WIYN telescope on Kitt Peak near Tucson, AZ, show structure in the gas and dust composition of Comet Hale-Bopp. The top row shows the distribution of gaseous cyanogen (CN) molecules on April 1 (left) and April 2 (right); the bottom row shows the distribution of dust particles on April 1 (left) and April 2 (right).

The spiral structure apparent in these pictures results from jets of gaseous material being ejected in a stream from the comet nucleus. The rotation of the comet nucleus, approximately once every eleven hours at the time these images were taken, wraps the ejected material around the nucleus in the spiral structure 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.

These images cover an area of about 100,000 km in diameter centered on the comet nucleus, an area visible to the unaided eye as the innermost, fuzzy "coma" of Hale-Bopp. These images were used to produce the combined false-color enhanced images immediately above. Notice that the structure has changed in both the gas and dust composition when compared with images from mid-march (below).

The images were provided courtesy of Beatrice Mueller and Nalin Samarasinha, NOAO.


image These six images of Comet Hale-Bopp have been processed so the gas and dust in the comet can be investigated separately. These images cover an area of about 100,000 km in diameter centered on the comet nucleus, an area visible to the unaided eye as the innermost, fuzzy "coma" of Hale-Bopp.

Taken through a filter that passes light in a narrow range of wavelengths, the top row of images shows cyanogen (CN) gas in the comet's coma. 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. Each image on top was taken within ten minutes of the image below it and the three pairs of images were taken on March 13, 14, and 15, 1997 with the WIYN telescope on Kitt Peak near Tucson, AZ. 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. The bright, circular objects in some images are background stars.

The images were processed and enhanced by Beatrice Mueller and Nalin Samarasinha, NOAO.


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Updated: 30Apr1997