Global Oscillation Amplitudes Excited by the Jupiter-Comet Collision
Session 25 -- Solar System and Heliosphere
Oral presentation, Wednesday, January 12, 10:15-11:45, Salon VI Room (Crystal Gateway)

## [25.04] Global Oscillation Amplitudes Excited by the Jupiter-Comet Collision

H. M. Van Horn$^1$ and U. Lee$^2$ (1. NSF and 2. Univ. Rochester)

The energy released during the collision of fragments of comet Shoemaker-Levy 9 with Jupiter in July 1994 may excite a spectrum of global oscillation modes. We estimate the maximum amplitudes to which the $p$-modes, discontinuity modes, inertial modes, and $r$-modes can be excited by assuming that the full kinetic energy of the fragment, which we take to be $10^{30}$ ergs, is converted into the energy of each individual mode. We have used two realistic Jovian models as the basis for our estimates: one with and one without the predicted \lq\lq plasma phase transition\rq\rq\ (PPT) of hydrogen. A density discontinuity in the planet's hydrogen-helium envelope is associated with the PPT. We find that high-frequency $p$-modes, with periods $\ltsim 15$ minutes, may be excited to sufficiently large amplitudes to be observable as Doppler shifts (velocity amplitudes $\gtsim$ several m s$^{-1}$) or temperature variations ($\delta T\gtsim 0.01$K) at the planetary surface. Inertial modes may also be observable. If the PPT exists in Jupiter, inertial modes with periods $\sim 8$ hours or $\sim 2.2$ days trapped in the surface region of the planet, above the PPT, may be detectable as temperature fluctuations of order $\delta T \sim 0.01$K. If the PPT does not exist, inertial modes with periods longer than $\sim 18$ hours may produce temperature fluctuations of order $\delta T \sim 0.01$K. Discontinuty modes associated with the PPT and $r$-modes unfortunately may not reach observable amplitudes.