EVOLUTION OF THE SHOEMAKER-LEVY 9 IMPACT SITES ON JUPITER These sequences show remarkable changes in the structure of the impact sites of Comet Shoemaker-Levy 9 on Jupiter in the months following the events. Some twenty to twenty-five fragments of the comet struck Jupiter during the week of 16-22 July 1994, generating intense fireballs and, later, earth-sized scars scattered in a band around the planet's southern hemisphere. These scars are believed to consist of soot-like material lofted high into the Jovian atmosphere by the impacts. At visible wavelengths, this material is dark relative to the bright cloud deck. The clouds themselves are quite dark at some near infrared wavelengths, due to absorption of sunlight by methane and hydrogen in the atmosphere. At these wavelengths, the material generated by the impact glows brightly in reflected sunlight compared to the dark disk of the planet. The images presented here were taken in the 1.7 and 2.3 micron methane absorption bands using the MAGIC infrared camera at the German-Spanish observatory on Calar Alto. As these frames demonstrate, the impact sites are still quite bright two months after the last fragment struck Jupiter. The structures are clearly spreading in longitude and now form an almost continuous band around the planet. Astronomers will be tracing the evolution of these sites to learn more about the high altitude winds in Jupiter's atmosphere. These images also show that the impacts are not creating structures similar to the cyclonic storm known as the Great Red Spot. Observers at the MPIA and elsewhere will continue to monitor the Jovian atmosphere in the coming weeks. These observations will become more and more difficult as the orbital motion of the two planets brings Jupiter closer and closer to the Sun as seen from Earth. INFORMATION ON INDIVIDUAL FRAMES July 25, 1994 1.7 and 2.3 micron Exposures These images were taken three days after the last fragment collided with Jupiter. A total of eleven impact sites appear. They are, from left to right: E, F and V blended together on the eastern (left) limb below the Great Red Spot, the three spots of the H impact, Q1 and N superimposed, and the massive complex on the western limb containing the D,G,R,S, and Q2 impact sites. These images were taken in the 1.7 and 2.3 micron absorption bands of methane. At these wavelengths, the Jovian cloud deck is dark relative to the spots, which shine by reflected sunlight. These frames come from MAGIC, the Max-Planck-Institut fuer Astronomie General Purpose Infrared Camera. MAGIC was mounted on the 3.5 meter telescope of the German-Spanish observatory on Calar Alto in southern Spain. ------------------------------------------------------------------------ August 17, 1994 1.7 and 2.3 micron Exposures These images show the planet Jupiter one month after the collision with Comet Shoemaker-Levy 9. The individual impact locations have spread considerably in longitude in the intervening month. The bright complex on the eastern (left) limb of the planet is the K and W fragment impact zone, and the structure near the western limb corresponds to the E/V/F scar seen at the eastern limb on 25 July. The faint star-like object to the lower left of Jupiter in the 2.3 micron frame is the innermost Galilean satellite, Io. The brighter moon is Callisto. At the time of observation, Io was in Jupiter's shadow and hence is not visible in the shorter wavelength (1.7 micron) exposure. Io is volcanically active and emits thermal radiation. Thus, we are seeing this satellite by "volcano light" in the 2.3 micron exposure. These frames were taken with the MPIA MAGIC infrared camera on the 3.5 meter telescope of the German-Spanish observatory on Calar Alto in southern Spain. ------------------------------------------------------------------------ September 20, 1994 1.7 and 2.3 micron Exposures These images show the dramatic changes in the structure of the comet impact zones in the two months since the collision of Comet Shoemaker-Levy 9 with Jupiter. The exposures show basically the same region of Jupiter as the 17 August frames. In this instance, the MAGIC camera was mounted on the smaller 2.2 meter telescope of the Calar Alto observatory, resulting in somewhat lower spatial resolution. Nevertheless, the images clearly show further spreading of the impact features into one or two continuous bands around the southern mid-latitudes of Jupiter. ------------------------------------------------------------------------ September 24, 1994 1.7 and 2.3 micron Exposures These images were also taken with the MAGIC camera mounted on the 2.2 meter telescope on Calar Alto. They show almost the same view of Jupiter as the first images in the sequence (25 July 1994). Note the locations of the Great Red Spot and the bright impact structure on the western (right) limb. This structure is the location where the D,G,R,S, and Q2 fragments struck the planet. Although the atmospheric seeing conditions were somewhat worse than in July, it is quite clear that the other impact zones have blurred into a continuous band. This band appears smoother than the impact structures in the other hemisphere seen in the September 20 images. The spreading clearly demonstrates that these impacts are not forming long-lasting atmospheric disturbances such as the Great Red Spot. The bright star-like object to the east (left) of Jupiter is the innermost Galilean moon, Io. PHOTO CREDITS Tom Herbst, Peter Bizenberger, Hermann Boehnhardt, Chris Davis, Doug Hamilton, Melvin Hoare, Mark McCaughrean, Jose Luis Ortiz Moreno. Contact Person: Tom Herbst Max-Planck-Institut fuer Astronomie Koenigstuhl 17 69117 Heidelberg, Germany tel. (49) 6221 528-223 fax. (49) 6221 528-246 e-mail (Internet) herbst@mpia-hd.mpg.de