Dr. J. Hunter Waite, Jr., Dr. G. Randall Gladstone, and other investigators analyzing data from the German Roentgensatellit (ROSAT) report the detection of bright x-ray emissions from Jupiter's northern hemisphere during the impact of one of the Comet Shoemaker-Levy 9 fragments on July 19.
Observations made with the ROSAT High Resolution Imager (HRI) during the impact of comet fragment K show intense x-ray emissions not present before or after the impact and clearly correlated with it. The emissions appear to originate from a region in Jupiter's high-latitude northern hemisphere that is connected by magnetic field lines to the impact site in the southern hemisphere. Electrons, energized by the impact and accelerated along the field lines to a conjugate region in the northern hemisphere, are the most likely source for the observed x-rays. The collision of these highly energetic electrons with the gases in Jupiter's upper atmosphere produces x-rays through a mechanism known as bremsstrahlung. The emissions observed at the time of the K fragment impact appear to be extremely well correlated with ultraviolet emissions seen by the Hubble Space Telescope. Besides the high-latitude x-ray emissions, emissions from near the magnetic equator have also been identified in the HRI data. These low-latitude emissions may be caused by precipitating energetic neutral atoms resulting from increased charge exchange reactions involving energetic ions in Jupiter's radiation belts.
The ROSAT satellite and x-ray telescope were built in Germany and are operated under the scientific leadership of the Max-Planck-Institut fuer extraterrestrische Physik. ROSAT was launched by NASA in 1990. The HRI was provided by the Harvard-Smithsonian Center for Astrophysics. The U.S. ROSAT Guest Observer Program is managed by NASA's Goddard Space Flight Center.
The members of the ROSAT Shoemaker-Levy 9 observing team are: J. H. Waite, Jr. (Principal Investigator), G. R. Gladstone, C. Na, S. A. Stern (all of Southwest Research Institute); F. Bagenal (University of Colorado); J. T. Clarke (University of Michigan); and A. C. Fabian and W. N. Brandt (Cambridge University). The ROSAT Project Scientist is J. Truemper (Max Planck Institute for Extraterrestrial Physics)
For more information contact
Hunter Waite or Randy Gladstone
Southwest Research Institute
PO Box 28510
San Antonio TX 78228-0510
phone: 210/522-3493 (Waite)