ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

2pUW8. Jovian acoustics: Short-range observation and long-range prediction.

Michael D. Collins

B. Edward McDonald

Naval Res. Lab., Washington, DC 20375

W. A. Kuperman

Scripps Inst. of Oceanogr., La Jolla, CA 92093

William L. Siegmann

Rensselaer Polytechnic Inst., Troy, NY 12180

Waves were observed propagating in the stratosphere of Jupiter near the impact sites of several of the fragments of Comet Shoemaker-Levy 9. Concentric rings appearing in Hubble Space Telescope images have tentatively been identified as gravity and acoustic waves based on their horizontal group speeds of 450 and 900 m/s. Interpreting the images is complicated by the fact that the outer ring is located amidst the debris of the collapsed fireball. Since the fireball rose back through the obliquely oriented path of the incoming fragment, the debris field is asymmetric and offset from the impact site. It is therefore unlikely that the outer ring is part of the debris. If waves are observed far from the impact sites, they might provide new information about the Jovian atmosphere. A three-dimensional adiabatic mode solution predicts that the Jovian zonal winds cause horizontal caustics to form to the east and west of the impact sites about 10 h after impact. An adiabatic mode solution has also been derived for gravity waves, which exhibit similar horizontal caustics. Although the acoustic and gravity wave equations are drastically different, the horizontal wave equations for the mode coefficients are identical.