Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-25T16:14:57.234Z Has data issue: false hasContentIssue false

The orbital motion and impact circumstances of Comet Shoemaker-Levy 9

Published online by Cambridge University Press:  02 August 2016

Paul W. Chodas
Affiliation:
Jet Propulsion Laboratory, California Institute Of Technology, 4800 Oak Grove Drive, Pasadena, Ca 91109, USA
Donald K. Yeomans
Affiliation:
Jet Propulsion Laboratory, California Institute Of Technology, 4800 Oak Grove Drive, Pasadena, Ca 91109, 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.

Two months after the discovery of comet Shoemaker-Levy 9 came the astonishing announcement that the comet would impact Jupiter in July 1994. Computing the orbital motion of this remarkable comet presented several unusual challenges. We review the pre-impact orbit computations and impact predictions for SL9, from the preliminary orbit solutions shortly after discovery to the final set of predictions before the impacts. The final set of predicted impact times were systematically early by an average of 7 minutes, probably due to systematic errors in the reference star catalogs used in the reduction of the fragments' astrometric positions. The actual impact times were inferred from the times of observed phenomena for 16 of the impacts. Orbit solutions for the fragments were refined by using the actual impact times as additional data, and by estimating and removing measurement biases from the astrometric observations. The final orbit solutions for 21 fragments are tabulated, along with final estimates of the impact times and locations. The pre-breakup orbital history of the comet was investigated statistically, via a Monte Carlo analysis. The progenitor nucleus of SL9 was most likely captured by Jupiter around 1929 ± 9 years. Prior to capture, the comet was in a low-eccentricity, low-inclination heliocentric orbit entirely inside Jupiter's orbit, or, less likely, entirely outside. The ensemble of possible pre-capture orbits is consistent with a group of Jupiter family comets known as the quasi-Hildas.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1996

References

Benner, L. A. M. & McKinnon, W. B. 1995 On the orbital evolution and origin of comet Shoemaker-Levy 9. Icarus 118, 155168.Google Scholar
Bhatt, H. C. 1994 IAU Circular 6039, July 27, 1994.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.CrossRefGoogle Scholar
Boslough, M., Crawford, D., Trucano, T., & Robinson, A. 1995 Numerical modeling of Shoemaker-Levy 9 impacts as a framework for interpreting observations. Geophys. Res. Lett. 22, 1821.Google Scholar
Campbell, J. K. & Synnott, S. P. 1985 Gravity field of the jovian system from Pioneer and Voyager tracking data. Astron. J. 90, 364372.CrossRefGoogle Scholar
Carlson, R. W., Weissman, P. R., Segura, M., Hui, J., Smythe, W. D., Johnson, T. V., Baines, K. H., Drossart, P., Encrenaz, Th., Leader, F. E. 1995a Galileo infrared observations of the Shoemaker-Levy 9 G impact fireball: A preliminary report. Geophys. Res. Lett. 22, 1557.Google Scholar
Carlson, R. W., Weissman, P. R., Hui, J., Smythe, W. D., Baines, K. H., Johnson, T. V., Drossart, P., Encrenaz, T., Leader, F., & Mehlman, R. 1995b Some timing and spectral aspects of the G and R collision events as observed by the Galileo near-infrared mapping spectrometer. In Proceedings of the European SL-9/Jupiter Workshop (eds. West, R. and Bohnhardt, H.) pp. 69-73. ESO.Google Scholar
Carusi, A., & Valsecchi, G. B. 1979 Numerical simulations of close encounters between Jupiter and minor planets. In Asteroids, (ed. Gehrels, T.), pp. 391416. University of Arizona Press.Google Scholar
Carusi, A., Kresak, L., Perozzi, E., Valsecchi, G. B. 1985 Long-term evolution of short-period comets. Adam Hilger Ltd. Google Scholar
Chapman, C. R., Merline, W. J., Klaasen, K., Johnson, T. V., Heffernan, C., Belton, M. J. S., Ingersoll, A. P., & The Galileo Imaging Team 1995 Preliminary results of Galileo direct imaging of S-L 9 impacts. Geophys. Res. Lett. 22, 1561.Google Scholar
Chodas, P. W. 1993 Estimating the impact probability of a minor planet with the earth. Bull. Am. Astron. Soc. 25, 1236.Google Scholar
Chodas, P. W., & Yeomans, D. K. 1993 The upcoming collision of comet Shoemaker-Levy 9 with Jupiter. Bull. Am. Astron. Soc. 25, 1042.Google Scholar
Chodas, P. W., & Yeomans, D. K. 1994a The impact of comet Shoemaker-Levy 9 with Jupiter. Bull. Am. Astron. Soc. 26, 1022.Google Scholar
Chodas, P. W., & Yeomans, D. K. 1994b Comet Shoemaker-Levy 9 impact times and impact geometries. Bull. Am. Astron. Soc. 26, 1569.Google Scholar
Chodas, P. W. & Yeomans, D. K. 1995 The pre-breakup orbital history of comet Shoemaker-Levy 9. Bull. Am. Astron. Soc. 27, 1111.Google Scholar
Chodas, P. W., Yeomans, D. K., & Sekanina, Z. 1994 IAU Circular 5941, February 24, 1994.Google Scholar
Colas, F., Tiphene, D., Lecacheux, J., Drossart, P., De Batz, B., Pau, S., Rouan, D., & Sevre, F. 1995 Near infrared imaging of SL9 impacts on Jupiter from Pic-du-Midi observatory. Geophys. Res. Lett. 22, 17651768.Google Scholar
Davies, M. E., Abalakin, V. K., Brahic, A., Bursa, M., Chovitz, B. H., Lieske, J. H., Seidelmann, P. K., Sinclair, A. T., & Tjuflin, Y. S. 1992 Report of the IAU/IAG/COSPAR working group on cartographic coordinates and rotational elements of the planets and satellites: 1991. Cel. Mech. 53 377397.Google Scholar
De Pater, I., Graham, J., & Jernigan, G. 1994 IAU Circular 6024, July 17, 1994.Google Scholar
Graham, J. R., De Pater, I., Jernigan, J. G., Liu, M. C., Brown, M. E. 1995 The fragment R collision: W. M. Keck Telescope Observations of SL9. Science 267, 1320–1223.Google Scholar
Hamilton, D. P., Herbst, T. M., Richichi, A., Bohnhardt, H., & Ortiz, J. L. 1995 Calar Alto observations of Shoemaker-Levy 9: Characteristics of the H and L impacts. Geophys. Res. Lett. 22, 24172420.Google Scholar
Hammel, H. B., Beebe, R. F., Ingersoll, A. P., Orton, G. S., Mills, J. R., Simon, A. A., Chodas, P. W., Clarke, J. T., Dejong, E., Dowling, T. E., Harrington, J., Huber, L. F., Karkoschka, E., Santori, C. M., Toigo, A., Yeomans, D. K., & West, R. A. 1995 Hubble Space Telescope imaging of Jupiter: atmospheric phenomena created by the impact of comet Shoemaker-Levy 9. Science 267, 12881296.CrossRefGoogle ScholarPubMed
Herbst, T. M., Hamilton, D. P., Bohnhardt, H., & Ortiz-Moreno, J. L. 1995 Near infrared imaging and spectroscopy of the SL-9 impacts from Calar Alto. Geophys. Res. Lett. 22, 24132416.Google Scholar
Jewitt, D., Luu, J., & Chen, J. 1993 Physical properties of split comet Shoemaker-Levy 9. Bull. Am. Astron. Soc. 25, 1042.Google Scholar
Kary, D. M., & Dones, L. 1995 Capture statistics of short-period comets: Implications for comet Shoemaker-Levy 9. Icarus, (submitted).Google Scholar
Kresák, L. 1979 Dynamical interrelations among comets and asteroids. In Asteroids, (ed. Gehrels, T.). pp. 289309. University of Arizona Press.Google Scholar
Lagage, P. O., Aldemard, P. H., Pantin, E., Jouan, R., Masse, P., Sauvage, M., Olof sson, G., Huldtgren, M., Nordh, L., Belmonte, J. A., Regulo, C., Rodriguez Espinosa, J. M., Vidal, L., Mosser, B., Ulla, A., & Gautier, D. 1995 Collision of Shoemaker-Levy 9 fragments A, E, H, L, Ql with Jupiter: Mid-Infrared light curves. Geophys. Res. Lett. 22, 17731776.Google Scholar
Lieske, J. H. 1977 Theory of motion of Jupiter's Galilean satellites. Astron. Astrophys. 56, 333352.Google Scholar
Lieske, J. H. 1994 Galilean satellite ephemerides E4. JPL Engineering Memorandum 314-545, June 19, 1994.Google Scholar
Lindal, G. F., Wood, G. E., Levy, G. S., Anderson, J. D., Sweetnam, D. N., Hotz, H. B., Buckles, B. J., Holmes, D. P., Doms, P. E., Eshleman, V. R., Tyler, G. L., & Croft, T. A. 1981 The atmosphere of Jupiter: An analysis of the Voyager radio science occultation measurements. J.G.R. 86, 87218727.Google Scholar
Marsden, B. G. 1993a IAU Circular 5726, March 27, 1993.Google Scholar
Marsden, B. G. 1993b IAU Circulars 5744-5745, April 3, 1993.Google Scholar
Marsden, B. G. 1993C IAU Circular 5800-5801, May 22, 1993.Google Scholar
Marsden, B. G. 1993d IAU Circular 5892, November 22, 1993.Google Scholar
Marsden, B. G. 1993e IAU Circular 5906, December 14, 1993.Google Scholar
Marsden, B. G. 1994a IAU Circulars 5936-5937, February 18-21, 1994.Google Scholar
Marsden, B. G. 1994b Minor Planet Circulars 23105-23107, February 26, 1994.Google Scholar
Martin, T. Z., Orton, G. S., Travis, L. D., Tamppari, L. K., & Claypool, I. 1995 Observation of Shoemaker-Levy impacts by the Galileo Photopolarimeter Radiometer. Science 268, 18751879.Google Scholar
Meadows, V., Crisp, D., Orton, G., Brooke, T., & Spencer, J. 1995 AAT IRIS observations for the SL-9 impacts and initial fireball evolution. In Proceedings of the European SL-9/Jupiter Workshop, (eds. West, R. and Bohnhardt, H.) pp. 129134. ESO.Google Scholar
Nakano, S. 1993 IAU Circular 5800, May 22, 1993.Google Scholar
Nicholson, P. D., Gierasch, P. J., Hayward, T. L., McGhee, C. A., Moersch, J. E., Squyres, S. W., Van Cleve, J., Matthews, K., Neugebauer, G., Shupe, D., WeinBerger, A., Miles, J. W., & Conrath, B. J. 1995 Palomar observations of the R impact of comet Shoemaker-Levy 9: I. Light curves. Geophys. Res. Lett. 22, 16131616.CrossRefGoogle Scholar
Orton, G. S., With Help From The NIMS, PPR, SSI, and UVS Experiment Teams 1995a Comparison of Galileo SL-9 impact observations. In Proceedings of the European SL-9/Jupiter Workshop, (eds. West, R. and Bohnhardt, H.), pp. 7580. ESO.Google Scholar
Orton, G., A'Hearn, M., Baines, K., Deming, D., Dowling, T., Goguen, J., Grif-Fith, C., Hammel, H., Hoffmann, W., Hunten, D., Jewitt, D., Kostiuk, T. et al. 1995b Collision of comet Shoemaker-Levy 9 with Jupiter observed by the NASA Infrared Telescope Facility. Science 267, 12771282.Google Scholar
Roeser, S. & Bastian, U. 1989 PPM: Positions and proper motions of 181731 stars north of -2.5 degrees declination for equinox and epoch J2000. Astronomisches Rechen-Institut, Heidelberg.Google Scholar
Scotti, J. V., & Melosh, H. J. 1993 Estimate of the size of comet Shoemaker-Levy 9 from a tidal breakup model. Nature 365, 733735.Google Scholar
Sekanina, Z. 1995 The splitting of the nucleus of comet Shoemaker-Levy 9. In Proceedings of the European SL-9/Jupiter Workshop, (eds. West, R. and Bohnhardt, H.), pp. 4355. ESO.Google Scholar
Sekanina, Z., & Yeomans, D. K. 1985 Orbital motion, nucleus precession, and splitting of period comet Brooks 2. Astron. J. 90, 23352352.Google Scholar
Sekanina, Z., Chodas, P. W., & Yeomans, D.K. 1994 Tidal disruption and the appearance of periodic comet Shoemaker-Levy 9. Astron. Astrophys. 289, 607636.Google Scholar
Shoemaker, C. S., Shoemaker, E. M., & Levy, D. 1993 IAU Circular 5725, March 26, 1993.Google Scholar
Standish, E. M. 1990 The observational basis for JPL's DE200, the planetary ephemerides of the Astronomical Almanac. Astron. Astrophys. 233, 252271.Google Scholar
Takeuchi, S., Hasegawa, H., Watanabe, J., Yamashita, T., Abe, M., Hirota, Y., Nishi-Hara, E., Okumura, S., & Mori, A. 1995 Near-IR imaging observations of the cometary impact into Jupiter: Time variation of radiation from impacts of fragments C, D, and K. Geophys. Res. Lett. 22, 1581.Google Scholar
Tancredi, G., Lindgren, M., & Lagerkvist, C.-I. 1993 IAU Circular 5892, November 22, 1993.Google Scholar
Tancredi, G., Lindgren, M., & Rickman, H. 1990 Temporary satellite capture and orbital evolution of comet P/Helin-Roman-Crockett. Astron. Astrophys. 239, 375380.Google Scholar
Tozzi, G. P., Richichi, A., & Ferrara, A. 1995 High temporal resolution near-IR observations of impacts H and Q from Calar Alto and interpretation. In IAU Colloquium 156: The Collision of Comet P/Shoemaker-Levy 9 and Jupiter, p. 111.Google Scholar
Watanabe, J., Yamashita, T., Hasegawa, H., 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. Japan 47, L21.Google Scholar
Yeomans, D. K., & Chodas, P. W. 1993a IAU Circular 5807, May 28, 1993.Google Scholar
Yeomans, D. K., & Chodas, P. W. 1993b Minor Planet Circular 22197, June 4, 1993.Google Scholar
Yeomans, D. K., & Chodas, P. W. 1993c The collision of comet Shoemaker-Levy 9 with Jupiter in July 1994. JPL Interoffice Memorandum 314.10-50, July 21,1993.Google Scholar
Yeomans, D. K., & Chodas, P. W. 1993d IAU Circular 5909, December 17, 1993.Google Scholar
Yeomans, D. K., & Chodas, P. W. 1994a Comet Shoemaker-Levy 9 impact times. JPL Interoffice Memorandum 314.10-87, August 2, 1994.Google Scholar
Yeomans, D. K., & Chodas, P. W. 1994b Comet Shoemaker-Levy 9 in orbit about Jupiter. Bull. Am. Astron. Soc. 26, p. 3.Google Scholar
Yeomans, D. K., & Chodas, P. W. 1995 Predicting close earth approaches of asteroids and comets. In Hazards Due to Comets and Asteroids, (ed. Gehrels, T.), pp. 241258. University of Arizona Press.Google Scholar
Zahnle, K., & Mac Low, M.-M. 1995 A simple model for the light curve generated by Shoemaker-Levy 9 impact. J. Geophys. Res. 100, 16885.Google Scholar