Comet Shoemaker-Levy 9 fragment size estimates: How big was the parent body?
The impact of Comet Shoemaker-Levy 9 on Jupiter in July, 1994, was the largest, most energetic impact event on a planet ever witnessed. Because it broke up during a close encounter with Jupiter in 1992, it was bright enough to be discovered more than a year prior to impact, allowing the scientific community an unprecedented opportunity to assess the effects such an event would have. Many excellent observations were made from Earth-based telescopes, the Hubble Space Telescope (HST) and the Galileo spacecraft en route to Jupiter. In this paper, these observations are used in conjunction with computational simulations performed with the CTH shock-physics hydrocode to determine the sizes of the fifteen fragments that made discernible impact features on the planet. To do this, CTH was equipped with a radiative ablation model and a post-processing radiative ray-trace capability that enabled light-flux predictions (often called the impact flash) for the viewing geometries of Galileo and ground-based observers. The five events recorded by Galileo were calibrated to give fragment size estimates. Compared against ground-based and HST observations, these estimates were extended using a least-squares analysis to assess the impacts of the remaining ten fragments. Some of the largest impacts (L, G and K) were greater that 1 km in diameter but the density of the fragments was low, about 0.25 g/cm{sup 3}. The volume of the combined fifteen fragments would make a sphere 1.8 km in diameter. Assuming a pre-breakup density of 0.5 g/cm{sup 3}, the parent body of Shoemaker-Levy 9 had a probable diameter of 1.4 km. The total kinetic energy of all the impacts was equivalent to the explosive yield of 300 Gigatons of TNT.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); National Aeronautics and Space Administration, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 485982
- Report Number(s):
- SAND-97-1124C; CONF-9504147-; ON: DE97007427; TRN: 97:003960
- Resource Relation:
- Conference: International conference on near-earth objects, New York, NY (United States), 23-26 Apr 1995; Other Information: PBD: 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
Comet Shoemaker-Levy 9/Jupiter collision observed with a high resolution speckle imaging system
NUMERICAL MODELING OF THE DISRUPTION OF COMET D/1993 F2 SHOEMAKER-LEVY 9 REPRESENTING THE PROGENITOR BY A GRAVITATIONALLY BOUND ASSEMBLAGE OF RANDOMLY SHAPED POLYHEDRA