The top three images show X-ray emissions from Jupiter as observed by the ROSAT High Resolution Imager (HRI) before, during, and after the impact of fragment K of Comet Shoemaker-Levy 9 on July 19. The middle panel shows intense x-ray emissions detected immediately following the impact. These emissions appear to originate from a region in Jupiter's midlatitude northern hemisphere that is connected by magnetic field lines to the impact site in the southern hemisphere. We believe the emissions result from the impact of energetic electrons that were either a) accelerated along the magnetic field lines from the impact site to the conjugate region, or b) precipitated by impact-induced pitch-angle scattering from Jupiter's trapped radiation belts (similar to the Earth's Van Allen belts, although much larger and filled with more energetic particles). 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 x-ray emissions appear to be very well correlated with ultraviolet emissions from the same region observed by the Hubble Space Telescope near the time of the K fragment impact.
The lower plot shows the x-ray brightness of Jupiter before and during the impacts of the Shoemaker-Levy 9 fragments. While the K-fragment impact is the most obvious feature in the lightcurve, there are also hints of similar emissions following the P2 and W impacts.
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, K. Franke (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 director of the ROSAT project is J. Truemper (Max Planck Institute for Extraterrestrial Physics); the U.S. project scientist is Rob Petre (NASA Goddard Space Flight Center).
For more information contact
Hunter Waite or Randy Gladstone
Southwest Research Institute
PO Box 28510
San Antonio TX 78228-0510
fax: 210/647-4325
phone: 210/522-3493 (Waite)
210/522-3581 (Gladstone)
e-mail: hunter@swri.space.swri.edu
randy@whistler.space.swri.edu
