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Dynamical History of the Oort Cloud

Published online by Cambridge University Press:  12 April 2016

Paul R. Weissman
Paul R. Weissman*
Affiliation:
Earth and Space Sciences Division Jet Propulsion Laboratory 4800 Oak Grove Drive Pasadena, CA 91109, USA

Abstract

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Dynamical studies during the past decade have resulted in an almost explosive increase in our understanding of the Oort cloud of comets, which surrounds the solar system. Cometary orbits in the cloud evolve under the complex interaction of stellar, galactic, and giant molecular cloud perturbations, as well as planetary and nongravitational perturbations when the orbits re-enter the planetary region. Evidence has continued to build for a dense, inner Oort cloud of comets which acts as a reservoir to replenish the outer cloud as comets there are stripped away. A ring of comets beyond the orbit of Neptune, which may be the source of the short-period comets, is also likely. Both the estimated number and mass of comets in the Oort cloud have grown such that the total mass may be comparable to the mass of the planets. Temporal variations in the flux of comets from the Oort cloud into the planetary region by a factor of 50% are typical, and by factors of 20 to 200 are possible. The most intense cometary “showers” may have serious implications for biological extinction events on Earth as well as for the impact history of planets and satellite systems. Comets in the Oort cloud are processed by galactic cosmic rays, heated by nearby supernovae, eroded by interstellar dust impacts, and disrupted by mutual collisions (in the inner cloud). A detailed estimate of the Oort cloud’s dynamical history is not possible because of the inability to reconstruct the Sun’s varying galactic motion over the history of the solar system, and because of uncertainty over where comets actually formed. However, it is likely that a substantial fraction of the original Oort cloud population has been lost to interstellar space. We are approaching the time when Oort clouds around other stars may be detectable, though searches to date have so far been negative.

Type
Section III: Comets, Origins, and Evolution
Information
International Astronomical Union Colloquium , Volume 116 , Issue 1: Comets in the Post-Halley Era , 1989 , pp. 463 - 486
Copyright
Copyright © Kluwer 1991

References

Allen, C.W. (1973) Astrophysical Quantities, Athlone Press, London, 310 pp.Google Scholar
Anderson, J.D., and Standish, E.M. Jr. (1986) Dynamical evidence for Planet X. In The Galaxy and the Solar System, eds. Smoluchowski, R., Bancali, J.N., and Matthews, M. S., Univ. Arizona Press, Tucson, pp. 286–296.Google Scholar
Antonov, V.A., and Latyshev, I.N. (1972) Determination of the form of the Oort cometary cloud as the Hills surface in the Galactic field. In The Motion, Evolution of Orbits, and Origin of Comets, eds. Chebotarev, G. A., Kazimirchak-Polonskaya, E.I., and Marsden, B. G., D. Reidel, Dordrecht, pp. 341–345.Google Scholar
Bahcall, J.N. (1984) Self-consistent determination of the total amount of matter near the Sun. Astrophys. J. 276, 169–181.Google Scholar
Bahcall, J.N., and Bahcall, S. (1985) The Sun’s motion perpendicular to the galactic plane. Nature 316, 706–708.Google Scholar
Bailey, M.E. (1983) Comets, planet X, and the orbit of Neptune. Nature 302, 399–400.CrossRefGoogle Scholar
Bailey, M.E. (1984) The steady-state 1/a distribution and the problem of cometary fading. Mon. Not. Roy. Astron. Soc. 211, 347–368.CrossRefGoogle Scholar
Bailey, M.E. (1986) The mean energy transfer rate to comets in the Oort cloud and implications for cometary origins. Mon. Not. Roy. Astron. Soc. 218, 1–30.Google Scholar
Bailey, M.E., and Stagg, C.R. (1988) Cratering constraints on the inner Oort cloud: Steady-state models. Mon. Not. Roy. Astron. Soc. 235, 1–35.CrossRefGoogle Scholar
Biermann, L. (1978) Dense interstellar clouds and comets. In Astronomical Papers Dedicated to Bengt Stromgren, eds. Reiz, A. and Anderson, T., Copenhagen Obs., pp. 327–335.Google Scholar
Brin, G.D., and Mendis, D.A. (1979) Dust release and mantle development in comets. Astrophys. J. 229, 402–408.Google Scholar
Byl, J. (1983) Galactic perturbations on nearly parabolic cometary orbits. Moon & Planets 29, 121–137.Google Scholar
Cameron, A.G.W. (1962) The formation of the sun and planets. Icarus 1, 13–69.Google Scholar
Cameron, A.G.W. (1978) The primitive solar accretion disc and the formation of the planets. In The Origin of the Solar System, ed. Dermott, S. F., John Wiley & Sons, New York, pp. 49–75.Google Scholar
Clube, S.V.M., and Napier, W.M. (1982) Spiral arms, comets and terrestrial catastrophism. Quart. J. Roy. Astron. Soc. 23, 45–66.Google Scholar
Clube, S.V.M., and Napier, W.M. (1984) Comet capture from molecular clouds: A dynamical constraint on star and planet formation. Mon. Not. Roy. Astron. Soc. 208, 575–588.Google Scholar
Davis, M., Hut, P., and Muller, R.A. (1984) Extinction of species by periodic comet showers. Nature 308, 715–717.Google Scholar
Delsemme, A.H. (1987) Galactic tides affect the Oort cloud: An observational confirmation. Astron. & Astrophys. 187, 913–918.Google Scholar
Duncan, M., Quinn, T., and Tremarne, S. (1987) The formation and extent of the solar system comet cloud. Astron. J. 94, 1330–1338.Google Scholar
Duncan, M., Quinn, T., and Tremarne, S. (1988) The origin of short-period comets. Astrophys. J. 328, L69–L73.CrossRefGoogle Scholar
Everhart, E. (1967) Intrinsic distributions of cometary perihelia and magnitudes. Astron. J. 72, 1002–1011.Google Scholar
Fernandez, J.A. (1980) On the existence of a comet belt beyond Neptune. Mon. Not. Roy. Astron. Soc. 192, 481–491.Google Scholar
Fernandez, J.A. (1982) Dynamical aspects of the origin of comets. Astron J. 87, 1318–1332.Google Scholar
Fernandez, J.A. (1990) Statistical and evolutionary aspects of cometary orbits. In Comets in the Post-Halley Era, eds. Newburn, R. L. Jr., Rahe, J., and Neugebauer, M. M., Kluwer, Dordrecht, in press.Google Scholar
Fernandez, J.A., and Ip, W.-H. (1981) Dynamical evolution of a cometary swarm in the outer planetary region. Icarus 47, 470–479.Google Scholar
Fernandez, J.A., and Ip, W.-H. (1987) Time dependent injection of Oort cloud comets into Earth-crossing orbits. Icarus 71, 46–56.Google Scholar
Grieve, R.A.F. (1987) Terrestrial impact structures. Ann. Rev. Earth & Planet Sci. 17, 245–270.CrossRefGoogle Scholar
Halley, E. (1705) A Synopsis of the Astronomy of Comets. London, 24 pp.Google Scholar
Harrington, R.S. (1985) Implications of the observed distributions of very long-period comet orbits. Icarus 61, 60–62.Google Scholar
Heisler, J., and Tremarne, S. (1986) The influence of the galactic tidal field on the Oort comet cloud. Icarus 65, 13–26.Google Scholar
Heisler, J., Tremarne, S., and Alcock, C. (1987) The frequency and intensity of comet showers from the Oort cloud. Icarus 70, 269–288.Google Scholar
Heisler, J. (1990) Monte Carlo simulations of the Oort comet cloud. Icarus, submitted.Google Scholar
Hills, J.G. (1981) Comet showers and the steady-state infall of comets from the Oort cloud. Astron. J. 86, 1730–1740.Google Scholar
Hills, J.G. (1984) Dynamical constraints on the mass and perihelion distance of Nemesis and the stability of its orbit. Nature 311, 636–638.Google Scholar
Hoffman, A. (1985) Patterns of family extinction depend on definition and geologic timescale. Nature 315, 659–662.Google Scholar
Hut, P., and Weissman, P.R. (1985) Dynamical evolution of cometary showers. Bull. Amer. Astron. Soc. 17, 690 (abstract).Google Scholar
Hut, P., and Tremaine, S. (1985) Have interstellar clouds disrupted the Oort comet cloud? Astron. J. 90, 1548–1557.Google Scholar
Hut, P., Alvarez, W., Elder, W.P., Hanson, T., Kauffmann, E.G., Keller, G., Shoemaker, E. M., and Weissman, P.R. (1987) Comet showers as a cause of stepwise extinctions. Nature 329, 118–126.Google Scholar
Innanen, K.A., Patrick, A.T., and Duley, W.W. (1978) The interaction of the spiral density wave and the Sun’s galactic orbit. Astrophys. Space Sci. 57, 511–515.Google Scholar
Kyte, F.T. (1988) The extraterrestrial component in marine sediments: Description and interpretation. Paleoceanography 3, 235–247.Google Scholar
Johnson, R.E., Cooper, J.F., Lanzerotti, L.J., and Strazzula, G. (1987) Radiation formation of a non-volatile comet crust. Astron. Astrophys. 187, 889–892.Google Scholar
Kuiper, G.P., 1951. On the origin of the solar system. In Astrophysics, ed. Hynek, J. A., McGraw Hill, New York, pp. 357–424.Google Scholar
Marochnik, L.S., Mukhin, L.M., and Sagdeev, R.Z. (1988) Estimates of mass and angular momentum in the Oort cloud. Science 242, 547–550.Google Scholar
Marsden, B.G., Sekanina, Z., and Yeomans, D.K. (1973) Comets and nongravitational forces. V. Astron. J. 78, 211–225.Google Scholar
Marsden, B.G., Sekanina, Z., and Everhart, E. (1978) New osculating orbits for 110 comets and the analysis of the original orbits of 200 comets. Astron J. 83, 64–71.Google Scholar
McGlynn, T.A. and Chapman, R.D. (1989) On the nondetection of extrasolar comets. Astrophys. J. 346, L105–108.Google Scholar
Mihalas, D., and Binney, J. (1981) Galactic Astronomy, Structure and Kinematics, Freeman, W. H., San Francisco, 597 pp.Google Scholar
Morris, D.E., and Muller, R.A. (1986) Tidal gravitational forces: The infall of “new” comets and comet showers. Icarus 65, 1–12.Google Scholar
Nezhinskij, E.M. (1972) On the stability of the Oort cloud. In The Motion, Evolution of Orbits, and Origin of Comets, eds. Chebotarev, G. A., Kazimirchak-Polonskaya, E.I., and Marsden, B. G., D. Reidel, Dordrecht, pp. 335–340.CrossRefGoogle Scholar
Oort, J.H. (1950) The structure of the cloud of comets surrounding the solar system and a hypothesis concerning its origin. Bull. Astron. Inst. Neth. 11, 91–110.Google Scholar
Oort, J.H., and Schmidt, M. (1951) Differences between new and old comets. Bull. Astron. Inst. Neth. 11, 259–269.Google Scholar
Öpik, E. (1932) Note on stellar perturbations of nearly parabolic orbits. Proc. Amer. Acad. Arts. & Sci. 67, 169–183.Google Scholar
Peale, S.J. (1989) On the density of Halley’s comet. Icarus 82, 36–49.CrossRefGoogle Scholar
Prialnik, D., and Bar-Nun, A. (1987) On the evolution and activity of cometary nuclei. Astrophys. J. 313, 893–905.Google Scholar
Rampino, M.R., and Stothers, R.B. (1984) Terrestrial mass extinctions, cometary impacts, and the sun’s motion perpendicular to the galactic plane. Nature 308, 709–712.Google Scholar
Raup, D.M., and Sepkoski, J.J. (1984) Periodicity of extinctions in the geologic past. Proc. Natl. Acad. Sci. USA 81, 801–805.CrossRefGoogle Scholar
Rickman, H. (1986) Masses and densities of comets Halley and Kopff. In Comet Nucleus Sample Return, ESA SP-249, pp. 195–205.Google Scholar
Safronov, V.S. (1972) Evolution of the Protoplanetary Cloud and Formation of the Earth and Planets, NASA TT-F-677 (Nauka Press, Moscow, 1969).Google Scholar
Sagdeev, R.Z., Elyasberg, P.E., and Moroz, V.I. (1987) Is the nucleus of comet Halley a low density body? Nature 331, 240–242.Google Scholar
Schwartz, R.D., and James, P.B. (1984) Periodic mass extinctions and the Sun’s oscillation about the galactic plane. Nature 308, 712–713.CrossRefGoogle Scholar
Sekanina, Z. (1976) A probability of encounter with interstellar comets and the likelihood of their existence. Icarus 27, 123–133.Google Scholar
Shoemaker, E.M., and Wolfe, R.F. (1984) Evolution of the Uranus-Neptune planetesimal swarm. Lunar Planet Sci. Conf. XV, 780-781 (abstract).Google Scholar
Shoemaker, E.M., and Wolfe, R.F. (1986) Mass extinctions, crater ages, and comet showers. In The Galaxy and the Solar System, eds. Smoluchowski, R., Bahcall, J.N., and Matthews, M. S., Univ. Arizona Press, Tucson, pp. 338–386.Google Scholar
Smoluchowski, R., and Torbett, M. (1984) The boundary of the solar system. Nature 311, 38–39.Google Scholar
Stern, S.A. (1986) The effects of mechanical interaction between the interstellar medium and comets. Icarus 68, 276–283.Google Scholar
Stern, S.A. (1988) Collisions in the Oort cloud. Icarus 73, 499–507.Google Scholar
Stern, S.A. (1990) ISM induced erosion and gas dynamical drag in the Oort cloud. Icarus, in press.CrossRefGoogle Scholar
Stern, S.A., and Shull, J.M. (1988) The thermal evolution of comets in the Oort cloud by stars and supernovae. Nature 332, 407–411.Google Scholar
Stern, S.A., Stocke, J., and Weissman, P.R. (1990) An IRAS search for extra-solar Oort clouds. Icarus, submitted.Google Scholar
Stern, S.A., Shull, M.J., and Brandt, J.C. (1990b) The evolution and detectability of comet clouds during post main sequence stellar evolution. Nature, in press.Google Scholar
Thaddeus, P., and Chanan, G.A. (1985) Cometary impacts, molecular clouds, and the motion of the Sun perpendicular to the galactic plane. Nature 314, 73–75.Google Scholar
Torbett, M.V., and Smoluchowski, R. (1984) Orbital stability of an unseen solar companion linked to periodic extinction events. Nature 311, 641–642.Google Scholar
Tremarne, S. (1986) Is there evidence for a solar companion. In The Galaxy and the Solar System, eds. Smoluchowski, R., Bahcall, J.N., and Matthews, M. S., Univ. Arizona Press, Tucson, pp. 409–416.Google Scholar
Valtonen, M.J. (1983) On the capture of comets into the inner solar system. Observatory 103, 1–4.Google Scholar
Valtonen, M.J. and Innanen, K.A. (1982) The capture of interstellar comets. Astrophys. J. 255, 307–315.CrossRefGoogle Scholar
van Woerkom, A.F.F. (1948) On the origin of comets. Bull. Astron. Inst. Neth. 10, 445–472.Google Scholar
Wallis, M.K. (1980) Radiogenic melting of primordial comet interiors. Nature 284, 431–432.Google Scholar
Weissman, P.R. (1979) Physical and dynamical evolution of long-period comets. In Dynamics of the Solar System, ed. Duncombe, R. L., D. Reidel, Dordrecht, pp. 277–282.Google Scholar
Weissman, P.R. (1980) Stellar perturbations of the cometary cloud. Nature 288, 242–243.Google Scholar
Weissman, P.R. (1982) Dynamical history of the Oort cloud. In Comets, ed. Wilkening, L. L., Univ. Arizona Press, Tucson, pp. 637–658.CrossRefGoogle Scholar
Weissman, P.R. (1985a) Dynamical evolution of the Oort cloud. In Dynamics of Comets: Their Origin and Evolution, eds. Carusi, A. and Valsecchi, G. B., D. Reidel, Dordrecht, pp. 87–96.Google Scholar
Weissman, P.R. (1985b) Terrestrial impactors at geologic boundary events: Comets or asteroids? Nature 314, 517–518.Google Scholar
Weissman, P.R. (1986a) The mass of the Oort cloud: A post Halley reassessment. Bull. Amer. Astron. Soc. 18, 799 (abstract).Google Scholar
Weissman, P.R. (1986b) The Oort cloud and the galaxy: Dynamical interactions. In The Galaxy and the Solar System, eds. Smoluchowski, R., Bahcall, J.N., and Matthews, M. S., Univ. Arizona Press, Tucson, pp. 204–237.Google Scholar
Weissman, P.R. (1986c) Are cometary nuclei really pristine? In The Comet Nucleus Sample Return Mission, ESA SP-249, pp. 15–25.Google Scholar
Weissman, P.R. (1990) The cometary impactor flux at the Earth. In Global Catastrophes in Earth History, GSA Special Paper 247, eds. Sharpton, V. and Ward, P., in press.Google Scholar
Whipple, F.L. (1964) The history of the solar system. Proc. Natl. Acad. Sci. USA 51, 711–718.Google Scholar
Whitmire, D.P., and Jackson, A.A. (1984) Are periodic mass extinctions driven by a distant solar companion? Nature 308, 713–715.Google Scholar
Whitmire, D.P., and Matese, J.J. (1985) Periodic comet showers and planet X. Nature 313, 36–38.Google Scholar
Wielen, R. (1977) The diffusion of stellar orbits derived from the observed age dependence of the velocity dispersions. Astron. Astrophys. 60, 263–275.Google Scholar
Yeomans, D.K. (1986) Physical interpretations from the motions of comets Halley and Giacobini-Zinner. In 20th ESLAB Symposium on the Exploration of Halley’s Comet, eds. Battrick, B., Rolfe, E.J., and Reinhard, R., ESA SP-250, 2, 419–425.Google Scholar
Zhou, L., and Kyte, F.T. (1988) The Permian-Triassic boundary event: A geochemical study of three Chinese sections. Earth & Planet. Sci. Lett. 90, 411–421.Google Scholar