Plume Development of the Shoemaker-Levy 9 Comet Impact

TL;DR

This study uses 3D hydrodynamic simulations to analyze plume formation after a comet impact on Jupiter, revealing a fast, atmospheric-dominated plume that separates from the impact site and exhibits specific velocity and asymmetry characteristics.

Contribution

The paper presents the first detailed 3D hydrodynamic models of plume development from Jovian comet impacts, highlighting the dynamics of atmospheric ejection and velocity distribution.

Findings

The fast-moving plume contains mostly Jovian atmosphere (>99.9%)

The plume 'pinches off' about 50 km below the 1 bar level

Ejecta velocity distribution follows approximately v^-1.4

Abstract

We have studied plume formation after a Jovian comet impact using the ZEUS-MP 2 hydrodynamics code. The three-dimensional models followed objects with 500, 750, and 1000 meter diameters. Our simulations show the development of a fast, upward-moving component of the plume in the wake of the impacting comet that "pinches off" from the bulk of the cometary material ~50 km below the 1 bar pressure level, ~100 km above the depth of greatest mass and energy deposition. The fast-moving component contains about twice the mass of the initial comet, but consists almost entirely (>99.9%) of Jovian atmosphere rather than cometary material. The ejecta rise mainly along the impact trajectory, but an additional vertical velocity component due to buoyancy establishes itself within seconds of impact, leading to an asymmetry in the ejecta with respect to the entry trajectory. The mass of the upward-moving component follows a velocity distribution M(>v) approximately proportional to v^-1.4 (v^-1.6 for the 750 m and 500 m cases) in the velocity range 0.1 < v < 10 km/s.