Hostname: page-component-78c5997874-dh8gc Total loading time: 0 Render date: 2024-11-20T06:16:11.390Z Has data issue: false hasContentIssue false
  • English
  • Français

Dynamics and chemistry of SL9 plumes

Published online by Cambridge University Press:  02 August 2016

Kevin Zahnle
Kevin Zahnle*
Affiliation:
NASA Ames Research Center, M.S. 245-3, Moffett Field, California 94035-1000, USA

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The SL9 impacts are known by their plumes. Several of these were imaged by HST towering 3000 km above Jupiter's limb. The heat released when they fell produced the famous infrared main events. The reentry shocks must have been significantly hotter than the observed color temperature would imply, which indicates that the shocks were radiatively cooled, and that most of the energy released on reentry was radiated. This allows us to use the infrared luminosities of the main event to estimate the energy of the impacts; we find that the R impact released some 0.3 — 1 x 1027 ergs. Shock chemistry generates a suite of molecules not usually seen on Jupiter. The chemistry reflects a wide range of different shock temperatures, pressures, and gas compositions. The primary product, apart from H2, is CO, the yield of which depends only weakly on the comet's composition, and so can be used to weigh the comet. Abundant water and S2 are consistent with a somewhat oxidized gas (presumably the comet itself), but the absence of SO2 and CO2 shows that conditions were neither too oxidizing nor the shocks too hot. Meanwhile, production of CS, CS2, and HCN appears to require a source in dry jovian air; i.e., the airbursts occurred above the jovian water table. Tidal disruption calculations and models of the infrared light curves agree on an average fragment diameter of about half a kilometer. Chemical products and atmospheric disruption models agree on placing the terminal explosions around the 1 to 4 bar levels. The plumes were spectacular because the explosions were shallow, not because the explosions were large.

Type
Research Article
Information
International Astronomical Union Colloquium , Volume 156: The Collision of Comet Shoemaker-Levy 9 and Jupiter , May 1996 , pp. 183 - 212
Copyright
Copyright © Cambridge University Press 1996

References

Ahrens, T., Takata, T., O'Keefe, J. D., & Orton, G. 1991 Impact of Comet Shoemaker-Levy 9 on Jupiter. Geophys. Res. Lett. 21, 1087–1090.Google Scholar
Anders, E. & Grevesse, N. 1989. Abundances of the elements: meteoritic and solar. Geochim. Cosmochim. Acta 53, 197–214.Google Scholar
Asphaug, E. & Benz, W. 1994. Density of comet Shoemaker-Levy 9 deduced by modelling breakup of the parent ‘rubble pile’. Nature 370, 120–124.Google Scholar
Asphaug, E. & Benz, W. 1996. Size, density, and structure of Comet Shoemaker-Levy 9 inferred by the physics of tidal breakup. Icarus (in press).Google Scholar
Boslough, M., Crawford, D., Robinson, A., & Trucano, T. 1994. Mass and penetration depth of Shoemaker-Levy 9 fragments from time-resolved photometry. Geophys. Res. Lett. 21, 1555–1558.Google Scholar
Boslough, M., Crawford, D., Trucano, T., & Robinson, A. 1995. Numerical modelling of Shoemaker-Levy 9 impacts as a framework for interpreting observations. Geophys. Res. Lett. 22, 1821–1824.CrossRefGoogle Scholar
Carlson, R., Weissman, P., Hui, J., Smythe, W., Baines, K., Johnson, T. V., Drossart, P., Encrenaz, T., Leader, F., & Mehlman, R. 1994. Galileo NIMS observations of the impact of comet Shoemaker-Levy 9 on Jupiter. EOS Trans. AGU 75, 401.Google Scholar
Carlson, R., Weissman, P., Segura, M., Hui, J., Smythe, W., Johnson, T. V., Baines, K., Drossart, P., Encrenaz, T., & Leader, F. 1995. Galileo infrared observations of the Shoemaker-Levy 9 G impact fireball: A preliminary report. Geophys. Res. Lett. 22, 1557–1560.Google Scholar
Carlson, R., Weissman, P., Hui, J., Smythe, W., Baines, K., Johnson, T. V., Drossart, P., Encrenaz, T., Leader, F., & Mehlman, R. 1995. Some timing and spectral aspects of the G and R collision events as observed by the Galileo near-infrared mapping spectrometer, In Proceedings: European Shoemaker-Levy 9 Conference (ed. West, R.), pp. 69–73.Google Scholar
Chapman, C., Merline, W., Klaasen, K., Johnson, T., Heffernan, C., Belton, M., Ingersoll, A., & The Galileo Imaging Team. 1995. Preliminary results of Galileo direct imaging of SL9 impacts. Geophys. Res. Lett. 22, 1561–1564.CrossRefGoogle Scholar
Chevalier, R., & Sarazin, C. 1994. Explosions of infalling comets in Jupiter's atmosphere. Astrophys. J. 429, 863–875.Google Scholar
Chyba, C., Thomas, P., & Zahnle, K. 1993. Nature 361, 40–44.Google Scholar
Crawford, D., Boslough, M., Trucano, T., & Robinson, A. 1994. Numerical simulations of fireball growth and ejecta distribution during Shoemaker-Levy 9 impact on Jupiter. EOS Trans. AGU 75, 404.Google Scholar
Crawford, D., Boslough, M., Trucano, T., & Robinson, A. 1994. The impact of comet Shoemaker-Levy 9 on Jupiter. Shock Waves 4, 47–50.Google Scholar
Crisp, D., & Meadows, V. 1995. Near-infrared imaging spectroscopy of the impacts of SL9 fragments C, D, G, K, N, R, V, and W with Jupiter. IAU Colloquium 156: The Collision of Comet P/Shoemaker-Levy 9 and Jupiter held at the Space Telescope Science Institute, p. 25.Google Scholar
De Pater, I. 1991. The Significance of Radio Observations for Planets, Physics Reports 200, 1–37.Google Scholar
Drossart, P., Encrenaz, T., Lecacheux, J., Colas, F., & Lagage, P. 1995. The time sequence of SL9/impacts H and L from infrared observations. Geophys. Res. Lett. 22, 1769–1772.Google Scholar
Fegley, B. & Lodders, K. 1994. Chemical models of the deep atmospheres of Jupiter and Saturn. Icarus 110, 117–154.Google Scholar
Field, G. & Ferrara, A. 1995. The behavior of fragments of Comet Shoemaker-Levy 9 in the atmosphere of Jupiter. Astrophys. J. 438, 957–967.Google Scholar
Field, G., Tozzi, G., & Stanga, R. 1995. Dust as the cause of spots on Jupiter. Astron. Astrophys. 294, L53–L55.Google Scholar
Friedson, A. J., Hoffman, W., Goguen, J., Deutsch, L., Orton, G., Hora, J., Dayal, A., Spitale, J., Wells, W. K., & Fazio, G. 1995. Thermal infrared lightcurves of the impact of Comet Shoemaker-Levy 9 fragment R. Geophys. Res. Lett. 22, 1569–1572.Google Scholar
Graham, J., De Pater, I., Jernigan, J., Liu, M., & Brown, M. 1995. W. M. Keck telescope observations of the comet P/Shoemaker-Levy 9 fragment R Jupiter collision. Science 267, 1320–1323.CrossRefGoogle Scholar
Hammel, H., Beebe, R., Ingersoll, A., Orton, G., Mills, J., Simon, A., Chodas, P., Clarke, J., De Jong, E., Dowling, T., Harrington, J., Huber, L., Karkoschka, E., Santori, C., Toigo, A., Yeomans, D., & West, R. 1995. Hubble Space Telescope imaging of Jupiter: atmospheric phenomena created by the impact of comet Shoemaker-Levy 9. Science 267, 1288–1296.Google Scholar
Ingersoll, A., and Kanamori, H. 1995. Waves from the impacts of Shoemaker-Levy 9 with Jupiter Nature 374, 706—708.Google Scholar
Ingersoll, A., Kanamori, H., & Dowling, T. 1994. Atmospheric gravity waves from the impact of Shoemaker-Levy 9 with Jupiter Geophys. Res. Lett. 21, 1083–1086.Google Scholar
Kim, S., Ruiz, M., Rieke, G., Rieke, M., Mac Low, M.-M., & Zahnle, K. 1995. The re-entry shock of the R fragment of Comet Shoemaker-Levy 9. Nature (submitted).Google Scholar
Knacke, R. F., Geballe, T. R., Noll, K. S., & Brooke, T. Y. 1994. Infrared spectra of the R post-impact events of comet Shoemaker-Levy 9. Bull. Amer. Astron. Soc. Special Sessions on SL9 26, 3.25.Google Scholar
Knacke, R. F., Fajardo-Acosta, S. B., Geballe, T. R., & Noll, K. S. 1995. IAU Colloquium 156, p. 59.Google Scholar
Lellouch, E., Paubert, G., Moreno, R., Festou, M., Bézard, B., Bockelée-Morvan, D., Colom, P., Crovisier, J., Encrenaz, T., Gautier, D., Marten, A., Despois, D., Strobel, D., & Slevers, A. 1995. Chemical and thermal response of Jupiter to the impact of comet Shoemaker-Levy 9. Nature 373, 592–595.Google Scholar
Mac Low, M.-M. & Zahnle, K. 1994. Explosion of Comet Shoemaker-Levy 9 on entry into the Jovian atmosphere, Astrophys. J. Lett. 434, L33–L36.Google Scholar
McGregor, P., Nicholson, P., & Allen, M. 1995. CASPIR observations of the collision of Comet Sheomaker-Levy 9 with Jupiter. Icarus (submitted).Google Scholar
McKinnon, WM. B., & Schenk, P. 1995. Estimates of comet fragment masses from impact crater chains on Callisto and Ganymede. Geophys. Res. Lett. 22, 1829–1832.Google Scholar
Meadows, V., Crisp, D., Orton, G., Brooke, T., & Spencer, J. 1994. AAT observations of Shoemaker-Levy 9 collisions with Jupiter, poster presented at the 26th Ann. Mtg., Div. Planet. Sci., Bethesda MD, Oct. 31-Nov. 4, 1994.Google Scholar
Melosh, H. J., Schneider, N., Zahnle, K., & Latham, D. 1990. Ignition of global wildfires at the Cretaceous/Tertiary boundary. Nature 343, 251–254.Google Scholar
Moses, J. I., Allen, M., & Gladstone, R. 1995. Post-SL9 sulfur photochemistry on Jupiter, Geophys. Res. Lett. 22, 1597–1600.Google Scholar
Nicholson, P., Gierasch, P., Hayward, T., McGhee, C., Moersch, J., Squyres, S., Van Cleve, J., Matthews, K., Neugebauer, G., Shupe, D., Weinberger, A., Miles, J., & Conrath, B. 1995a. Palomar observations of the impact of the R fragment of comet P/Shomeaker-Levy 9: Light curves. Geophys. Res. Lett. 22, 1613–1616.Google Scholar
Nicholson, P., Gierasch, P., Hayward, T., McGhee, C., Moersch, J., Squyres, S., Van Cleve, J., Matthews, K., Neugebauer, G., Shupe, D., Weinberger, A., Miles, J., & Conrath, B. 1995b. Palomar observations of the impact of the R fragment of comet P/Shomeaker-Levy 9: Spectra. Geophys. Res. Lett. 22, 1617–1620.CrossRefGoogle Scholar
Noll, K., McGrath, M., Trafton, L., Atreya, S., Caldwell, J., Weaver, H., Yelle, R., Barnet, C., & Edgington, S. 1995. HST spectroscopic observations of Jupiter after the collision of Comet Shoemaker-Levy 9. Science 267, 1307–1313.Google Scholar
Prinn, R., & Fegley, B. 1987. Bolide Impacts, acid rain, and biospheric traumas at the Cretaceous-Tertiary boundary. Earth Planet. Sci. Lett. 83 1–15.CrossRefGoogle Scholar
Shoemaker, E., Hassig, P., & Roddy, D. 1995. Numerical modelling of Shoemaker-Levy 9 impacts as a framework for interpreting observations. Geophys. Res. Lett. 22, 1825–1828.Google Scholar
Solem, J. C. 1994. Density and size of comet Shoemaker-Levy 9 deduced from a tidal breakup model. Nature 370, 349–351.Google Scholar
Sprague, A., Bjoraker, G., Hunten, D., Witteborn, F., Kozlowski, R., & Wooden, D. 1996. Water brought into Jupiter's atmosphere by fragments R and W of Comet SL-9. Icarus (in press).Google Scholar
Stoker, C. 1986. Moist convection: A mechanism for producing the vertical structure of the Jovian equatorial plumes. Icarus 67, 106–125.CrossRefGoogle Scholar
Takata, T., O'Keefe, J. D., Ahrens, T. J., & Orton, G. 1994. Comet Shoemaker-Levy 9: Impact on Jupiter and plume evolution. Icarus 109, 3–19.Google Scholar
Takata, T., Ahrens, T. J., & Harris, A. 1995. Comet Shoemaker-Levy 9: Fragment and progenitor impact energy. Geophys. Res. Lett. 22, 2433–2436.Google Scholar
Watanabe, J., Yamashita, T., Hasegawa, T., Takeuchi, S., Abe, M., Hirota, Y., Nishi-Hara, E., Okumura, S., & Mori, A. 1995. Near-IR observation of cometary impacts to Jupiter: Brightness variation of the impact plume of fragment K. Publ. Astron. Soc. Jpn. 47, L21–L24.Google Scholar
West, R., Karkoschka, E., Friedson, A., Seymour, M., Baines, K., & Hammel, H. 1995. Impact debris particles in Jupiter's stratosphere. Science 267, 1296–1301.Google Scholar
Yabe, T., Xiao, F., Zhang, D., Sasaki, S., Abe, Y., Kobayashi, N., & Terasawa, T. 1994. Effect of EOS on break-up of Shoemaker-Levy 9 entering jovian atmosphere. J. Geomag. Geolectr. 46, 657–662.Google Scholar
Young, R., Zahnle, K., & Mac Low, M.-M., 1995. Nonlinear propagating features in the stratosphere of Jupiter generated by the impact of SL-9. Bull. Amer. Astrom. Soc, (in press).Google Scholar
Zahnle, K. 1990. Atmospheric chemistry by large impacts. In Global Catastrophes in Earth History (eds. Sharpton, V. & Ward, P.). Geol. Soc. Am. Spec. Pap. 247 pp. 271-P288.Google Scholar
Zahnle, K., & Mac Low, M.-M. 1994. The collision of Jupiter and Comet Shoemaker-Levy 9. Icarus 108, 1–17.Google Scholar
Zahnle, K., & Mac Low, M.-M. 1995. A simple model for the light curve generated by a Shoemaker-Levy 9 impact. J. Geophys. Res. 100, 16885–16894.CrossRefGoogle Scholar
Zahnle, K., Mac Low, M.-M., Lodders, K., & Fegley, B. 1995. Sulfur chemistry in the wake of Shoemaker-Levy 9. Geophys. Res. Lett. 22, 1593–1596.Google Scholar
Zel'dovich, IA. B., & Raizer, YU. P. 1967. Physics of Shock Waves and High Temperature Hydrodynamic Phenomena Academic.Google Scholar