Space Science Reviews

, Volume 116, Issue 1–2, pp 421–439 | Cite as

Triton, Pluto, Centaurs, and Trans-Neptunian Bodies

  • Dale P. CruikshankEmail author


The diverse populations of icy bodies of the outer Solar System (OSS) give critical information on the composition and structure of the solar nebula and the early phases of planet formation. The two principal repositories of icy bodies are the Kuiper belt or disk, and the Oort Cloud, both of which are the source regions of the comets. Nearly 1000 individual Kuiper belt objects have been discovered; their dynamical distribution is a clue to the early outward migration and gravitational scattering power of Neptune. Pluto is perhaps the largest Kuiper belt object. Pluto is distinguished by its large satellite, a variable atmosphere, and a surface composed of several ices and probable organic solid materials that give it color. Triton is probably a former member of the Kuiper belt population, suggested by its retrograde orbit as a satellite of Neptune. Like Pluto, Triton has a variable atmosphere, compositionally diverse icy surface, and an organic atmospheric haze. Centaur objects appear to come from the Kuiper belt and occupy temporary orbits in the planetary zone; the compositional similarity of one well studied Centaur (5145 Pholus) to comets is notable. New discoveries continue apace, as observational surveys reveal new objects and refined observing techniques yield more physical information about specific bodies.


Triton Pluto Centaurs Kuiper Belt Objects ice infrared spectroscopy 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Andronico, G., Baratta, G.A., Spinella, F., and Strazzulla, G.: 1987, ‘Optical evolution of laboratoryproduced organics – applications to Phoebe, Iapetus, outer belt asteroids and cometary nuclei’, Astron. Astrophys. 184, 333–336.Google Scholar
  2. Barucci, M.A., Fulchignoni, M., Birlan, M., Doressoundiram, A., Romon, J., and Boehnhardt, H.: 2001, ‘Analysis of Trans-Neptunian and Centaur colours: continuous trend or grouping?’, Astron. Astrophys. 371, 1150–1154.CrossRefGoogle Scholar
  3. Barucci, M.A., Doressoundiram, A., and Cruikshank, D.P.: 2004, in M.C. Festou, H.U. Keller, and H.A. Weaver (eds.), Comets II, The University of Arizona Press, in press.Google Scholar
  4. Binzel, R.P. and Hubbard, W.B.: 1997, ‘Mutual events and stellar occultations’, in S.A. Stern and D.J. Tholen (eds.), in Pluto and Charon, The University of Arizona Press, Tucson, pp. 85-102.Google Scholar
  5. Bockelée-Morvan, D., Lellouch, E., Biver, N., Paubert, G., Bauer, J., Colom, P., and Lis, D.C.: 2001, ‘Search for CO gas in Pluto, Centaurs and Kuiper belt objects at radio wavelengths’, Astron. Astrophys. 377, 343–353.CrossRefGoogle Scholar
  6. Broadfoot, A.L., et al.: 1989, ‘Ultraviolet spectrometer observations of Neptune and Triton’, Science 246, 1459–1466.Google Scholar
  7. Brown, M.E.: 2003, Bull. Am. Astron. Soc. 35, 969 (abstract).Google Scholar
  8. Brown, M.E. and Calvin, W.M.: 2000, ‘Evidence for crystalline water and ammonia ices on Pluto’s satellite Charon’, Science 287, 107–109.CrossRefPubMedGoogle Scholar
  9. Brown, M.E., Trujillo, C., and Rabinowitz, D.: 2004, Astrophys. J. Lett., in press.Google Scholar
  10. Brown, R.H. and Cruikshank, D.P.: 1993, ‘Remote sensing of ices and ice-mineral mixtures in the outer solar system’, in C.M. Pieters, and P.A.J. Englert (eds.), Remote Geochemical Analysis: Elemental and Mineralogical Composition, The Cambridge University Press, pp. 455–468.Google Scholar
  11. Brown, R.H., Cruikshank, D.P., Veverka, J., Helfenstein, P., and Eluszkiewicz, J.: 1995, ‘Surface composition and photometric properties of Triton’, in D.P. Cruikshank (ed.), Neptune and Triton, The University of Arizona Press, Tucson, pp. 991–1030.Google Scholar
  12. Brown, R.H., Cruikshank, D.P., Pendleton, Y.J., and Veeder G.J.: 1998, ‘Identification of water ice on the Centaur 1997 CU26’, Science 280, 1430–1432.CrossRefPubMedGoogle Scholar
  13. Brown, R.H., Cruikshank, D.P., and Pendleton, Y.J.: 1999, ‘Water ice on Kuiper belt object 1996 TO66’, Astrophys. J. 519, L101–L104.CrossRefGoogle Scholar
  14. Calcagno, L., Foti, G., Torrisi, L., and Strazzulla, G.: 1985, ‘Fluffy layers obtained by ion bombardment of frozen methane Experiments and applications to Saturnian and Uranian satellites’, Icarus 63, 31–38.CrossRefGoogle Scholar
  15. Cruikshank, D.P.: 1987, ‘Dark matter in the solar system’, Adv. Space Res. 7, 109–120.CrossRefGoogle Scholar
  16. Cruikshank, D.P. (ed.): 1995, Neptune and Triton, The University of Arizona Press, Tucson, 1249 pp.Google Scholar
  17. Cruikshank, D.P. and Dalle Ore, C.M.: 2003, ‘Spectral models of Kuiper belt objects and Centaurs’, Earth, Moon, and Planets 92, 315–330.Google Scholar
  18. Cruikshank, D. P., Roush, T. L., Owen, T. C., Quirico, E., and de Bergh, C.: 1998a, ‘The surface compositions of Triton, Pluto and Charon’, in B. Schmitt, C. de Bergh, and M. Festou (eds.), Ices in the Solar System, Kluwer Academic Publishers, Dordrecht, pp. 655–684.Google Scholar
  19. Cruikshank, D.P., et al.: 1998b, ‘The composition of Centaur 5145 Pholus’, Icarus 135, 389–407.CrossRefGoogle Scholar
  20. Cruikshank, D.P., et al.: 1998c, Bull. Am. Astron. Soc. 30, 1094 (abstract).Google Scholar
  21. Cruikshank, D.P., Dalle Ore, C.M., Roush, T.L., Geballe, T.R., Owen, T.C., de Bergh, C., Cash, M.D., and Hartmann, W.K.: 2001, Icarus 153, 348–360.CrossRefGoogle Scholar
  22. Cruikshank, D.P., Roush, T.L., and Poulet, F.: 2003, ‘Quantitativemodeling of the spectral reflectance of Kuiper belt objects and Centaurs’, C. R. Physique 4, 783–789.Google Scholar
  23. Cruikshank, D.P., Dalle Ore, C.M., and Imanaka, H.: 2005, Icarus, submitted.Google Scholar
  24. Davies, J.K., Sykes, M.V., and Cruikshank, D.P.: 1993, ‘Near-infrared photometry and spectroscopy of the unusual minor planet 5145 Pholus (1992AD)’, Icarus 102, 166–169.CrossRefGoogle Scholar
  25. Doressoundiram, A., Tozzi, G.P., Barucci, M.A., Boehnhardt, H., Fornasier, S., and Romon, J.: 2003, ‘ESO Large Programme on Trans-Neptunian Objects and Centaurs: Spectroscopic Investigation of Centaur 2001 BL41 and TNOs (26181) 1996 GQ21 and (26375) 1999 DE9’, Astron. J. 125, 2721–2727.CrossRefGoogle Scholar
  26. Dotto, E., Barucci, M. A., and de Bergh, C.: 2003, C. R. Physique 4, 775–782.Google Scholar
  27. Douté, S., Schmitt, B., Quirico, E., Owen, T.C., Cruikshank, D.P., de Bergh, C., Geballe, T.R., and Roush, T.L.: 1999, ‘Evidence for methane segregation at the surface of Pluto’, Icarus 142, 421–444.CrossRefGoogle Scholar
  28. Dumas, C., Terrile, R.J., Brown, R.H., Schneider, G., and Smith, B.A.: 2001, ‘Hubble Space Telescope NICMOS spectroscopy of Charon’s leading and trailing hemispheres’, Astron. J. 121, 1163–1170.CrossRefGoogle Scholar
  29. Elliot, J.L., Dunham, E.W., Bosh, A.S., Silvan, S.M., Young, L.A., Wasserman, L.H., and Millis, R.L.: 1989, Icarus 77, 148–170.CrossRefGoogle Scholar
  30. Elliot, J.L. and Young, L.A.: 1992, Astron. J. 103, 991–1015.CrossRefGoogle Scholar
  31. Elliot, J.L., et al.: 1998, ‘Global warming on Triton’, Nature 393, 765–767.CrossRefGoogle Scholar
  32. Elliot, J.L., et al.: 2003, ‘The recent expansion of Pluto’s atmosphere’, Nature 424, 164–168.CrossRefGoogle Scholar
  33. Emery, J.P. and Brown, R.H.: 2003, ‘Constraints on the surface composition of Trojan asteroids from near-infrared (0.8-4.0 μm) spectroscopy’, Icarus 164, 104–121.CrossRefGoogle Scholar
  34. Fernández, J.A. and Brunini, A.: 2000, Icarus 145, 580–590.CrossRefGoogle Scholar
  35. Funato, U., Makino, J., Hut, P., Kokubo, E., and Kinoshita, D.: 2004, ‘The formation of Kuiper-belt binaries through exchange reactions’, Nature 427, 518–520.CrossRefPubMedGoogle Scholar
  36. Gaffey, S.J., McFadden, L.A., Nash, D., and Pieters, C.M.: 1993, ‘Ultraviolet, visible, and nearinfrared reflectance spectroscopy: laboratory spectra of geologic materials’, in C.M. Pieters and P.A.J. Englert (eds.), Remote Geochemical Analysis: Elemental and Mineralogical Composition, Cambridge University Press, New York, pp. 43–77.Google Scholar
  37. Goldreich, P., Lithwick, Y., and Sari, R.: 2002, ‘Formation of Kuiper-belt binaries by dynamical friction and three-body encounters’, Nature 420, 643–646.CrossRefPubMedGoogle Scholar
  38. Grundy, W.M., Buie, M.W., and Spencer, J.R.: 2002, ‘Spectroscopy of Pluto and Triton at 3–4 microns: possible evidence for wide distribution of nonvolatile solids’, Astron. J. 124, 2273–2278.CrossRefGoogle Scholar
  39. Hainaut, O.R. and Delsanti, A.C.: 2002, ‘Colors of minor bodies in the Outer solar system. A statistical analysis’, Astron. Astrophys. 389, 641–664.CrossRefGoogle Scholar
  40. Hartmann, W.K., Tholen, D.J., and Cruikshank, D.P.: 1987, ‘The relationship of active comets, ‘extinct’ comets, and dark asteroids’, Icarus 69, 33–50.CrossRefGoogle Scholar
  41. Hartmann, W.K., Tholen, D.J., Meech, K.J., and Cruikshank, D.P.: 1990, ‘2060 Chiron – colorimetry and cometary behavior’, Icarus 83, 1–15.CrossRefGoogle Scholar
  42. Jewett, D.C.: ‘From Kuiper belt object to cometary nucleus: The missing ultrared matter’, Astron. J. 123, 1039–1049.Google Scholar
  43. Jewitt, D. and Luu, J.: 1993, ‘Discovery of the candidate Kuiper belt object 1992 QB1’, Nature 362, 730–732.CrossRefGoogle Scholar
  44. Khare, B.N., Sagan, C., Arakawa, E.T., Suits, R., Callcot, T.A., and Williams, M.W.: 1984, ‘Optical constants of organic tholins produced in a simulated Titanian atmosphere - From soft X-ray to microwave frequencies’, Icarus 60, 127–137.CrossRefGoogle Scholar
  45. Khare, B.N., Thompson, W. R., Cheng, L., Chyba, C., Sagan, C., Arakawa, E. T., Meisse, C., and Tuminello, P.: 1993, ‘Production and optical constraints of ice tholin from charged particle irradiation of (1:6) C2H6/H2O at 77 K’, Icarus 103, 290–300, 1993.CrossRefGoogle Scholar
  46. Krasnopolsky, V.A. and Cruikshank, D.P.: 1995, ‘Photochemistry of Triton’s atmosphere and ionosphere’, J. Geohys. Res. 100, 21,271–21,286.Google Scholar
  47. Krasnopolsky, V.A. and Cruikshank, D.P.: 1999, ‘Photochemistry of Pluto’s atmosphere and ionosphere near perihelion’, J. Geophys. Res. 104, 21,979–21,996.Google Scholar
  48. Kuiper, G.P.: 1951, ‘On the origin of the solar system’, in J.A. Hynek (ed.), Astrophysics, New York: McGraw-Hill, New York, pp. 357–424.Google Scholar
  49. Lellouch, E., Laureijs, R., Schmitt, B., Quirico, E., de Bergh, C., Crovisier, J., and Coustenis, A.: 2000, ‘Pluto’s non-isothermal surface’, Icarus 147, 220–250.CrossRefGoogle Scholar
  50. Levison, H.F. and Morbidelli, A.: 2003, ‘The formation of the Kuiper belt by the outward transport of bodies during Neptune’s migration’, Nature 426, 419–421.CrossRefPubMedGoogle Scholar
  51. Luu, J., Jewitt, D., and Cloutis, E.: 1994, Icarus 109, 133–144.CrossRefGoogle Scholar
  52. McKinnon, W.B., Lunine, J.I., and Banfield, D.: 1995, ‘Origin and evolution of Triton’, in D.P. Cruikshank (ed.), Neptune and Triton, The University of Arizona Press, Tucson, pp. 807–877.Google Scholar
  53. Miner, E.D. and Wessen, R.R.: 2002, Neptune: The Planet, Rings and Satellites, Springer Praxis, Chichester, 297 pp.Google Scholar
  54. Noll, K.S.: 2004, Earth, Moon, and Planets 92, 395–407.Google Scholar
  55. Noll, K., Stephens, D., Grundy, W., Millis, R., Buie, M., Spencer, J., Tegler, S., Romanishin, W., and Cruikshank, D.: 2002, Bull. Am. Astron. Soc. 34, 849 (abstract).Google Scholar
  56. Oort, J.: 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
  57. Owen, T.C., Cruikshank, D.P., Roush, T., de Bergh, C., Brown, R. H., Bartholomew, M. J., Elliot, J., and Young, L. 1993, ‘Surface ices and the atmospheric composition of Pluto’, Science 261, 745–748.Google Scholar
  58. Poulet, F., Cuzzi, J.N., Cruikshank, D.P., Roush, T., and Dalle Ore, C.M.: 2002, ‘Comparison between the Shkuratov and Hapke scattering theories for solid planetary surfaces: Application to the surface composition of two Centaurs’, Icarus 160, 313–324.CrossRefGoogle Scholar
  59. Quirico, E., Douté, S., Schmitt, B., de Bergh, C., Cruikshank, D.P., Owen, T.C., Geballe, T.R., and Roush, T.L.: 1999, ‘Composition, physical state, and distribution of ices at the surface of Triton’, Icarus 139, 159–178.CrossRefGoogle Scholar
  60. Sicardy, B., et al.: 2003, ‘Large changes in Pluto’s atmosphere as revealed by recent stellar occultations’, Nature 424, 168–170.CrossRefPubMedGoogle Scholar
  61. Stansberry, J.A., Lunine, J.I., Hubbard, W.B., Yelle, R.V., and Hunten, D.M.: 1994, ‘Mirages and the nature of Pluto’s atmosphere’, Icarus 111, 503–513.CrossRefGoogle Scholar
  62. Stern, S.A., Buie, M.W., and Trafton, L.: 1997, ‘HST high-resolution images and maps of Pluto’, Astron. J. 113, 827–843.CrossRefGoogle Scholar
  63. Stern, S.A. and Kenyon, S.J.: 2003, ‘Collisions, accretion, and erosion in the Kuiper belt’, C. R. Physique 4, 803–808.Google Scholar
  64. Stone, E.C. and Miner, E.D: 1989, ‘The Voyager 2 encounter with the Neptunian system’, Science 146, 1417–1421.Google Scholar
  65. Strobel, D.F., Zhu, X., Summers, M.E., and Stevens, M.H.: 1996, ‘On the vertical thermal structure of Pluto’s atmosphere’, Icarus 120, 266–289.CrossRefGoogle Scholar
  66. Tholen, D.J. and Buie, M.W.: 1997, ‘The Orbit of Charon’, in S.A. Stern and D.J. Tholen (eds.), Pluto and Charon, The University of Arizona Press, Tucson, pp. 193–219.Google Scholar
  67. Tyler, G.L., Sweetnam, D.N., Anderson, J.D., Borutzki, S.E., Campbell, J.K., Kursinski, E.R., Levy, G.S., Lindal, G.F., Lyons, J.R., and Wood, G.E.: 1989, ‘Voyager radio science observations of Neptune and Triton’, Science 246, 1466–1473.Google Scholar
  68. Weidenschilling, S.J.: 2002, ‘On the origin of binary transneptunian objects’, Icarus 160, 212–215.CrossRefGoogle Scholar
  69. Weissman, P.R.: 1998, ‘The Oort cloud’, Scientific American 279, 84–89.PubMedGoogle Scholar
  70. Yelle, R.V., Lunine, J.L., and Hunten, D.M.: 1991, ‘Energy balance and plume dynamics in Triton’s lower atmosphere’, Icarus 89, 347–358.CrossRefGoogle Scholar
  71. Young, L.A., Elliot, J.L., Tokunaga, A., de Bergh, C., and Owen, T.: 1997, ‘Detection of gaseous methane on Pluto’, Icarus 127, 258–262.CrossRefGoogle Scholar
  72. Young, E.F., Binzel, R.P., and Crane, K.: 2001, ‘A two-color map of Pluto’s sub-Charon hemisphere’, Astron. J. 121, 552–561.CrossRefGoogle Scholar

Copyright information

© Springer Science + Business Media, Inc. 2005

Authors and Affiliations

  1. 1.NASA Ames Research CenterMoffett FieldUSA
  2. 2.Astrophysics Branch (Mail Stop 245-6)NASA Ames Research CenterMoffett FieldUSA

Personalised recommendations