The Surface Compositions of Triton, Pluto, and Charon

  • Dale P. Cruikshank
  • Ted L. Roush
  • Tobias C. Owen
  • Eric Quirico
  • Catherine De Bergh
Part of the Astrophysics and Space Science Library book series (ASSL, volume 227)


Neptune’s satellite Triton, and the planet-satellite binary Pluto and Charon, are the most distant planetary bodies on which ices have been directly detected. Triton and Pluto have very similar dimensions and mean densities, suggesting a similar or common origin. Through Earth-based spectroscopic observations in the near-infrared, solid N 2, CH 4, H 2 O, and CO have been found on both bodies, with the additional molecule CO 2 on Triton. N 2 dominates both surfaces, although the coverage is not spatially uniform. On Triton, the CH 2 and CO are mostly or entirely frozen in the N 2 matrix, while CO 2 may be spatially segregated. On Pluto, some CH 4 and the CO are frozen in the N 2 matrix, but there is evidence for additional CH 2 in a pure state, perhaps lying as a lag deposit on a subsurface layer of N 2. Despite their compositional and dimensional similarities, Pluto and Triton are quite different from one another in detail. Additional hydrocarbons and other volatile ices have been sought spectroscopically but have not yet been detected. The only molecule identified on Pluto’s satellite Charon is solid H 2 O, but the spectroscopic data are of low precision and admit the presence of other ices such as CH 4.


Optical Constant Spectral Reflectance Kuiper Belt Outer Solar System Intimate Mixture 
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Copyright information

© Springer Science+Business Media Dordrecht 1998

Authors and Affiliations

  • Dale P. Cruikshank
    • 1
  • Ted L. Roush
    • 1
    • 2
  • Tobias C. Owen
    • 3
  • Eric Quirico
    • 4
  • Catherine De Bergh
    • 5
  1. 1.NASA Ames Research CenterMoffett FieldUSA
  2. 2.San Francisco State Univ.USA
  3. 3.Institute for AstronomyUniversity of HawaiiHonoluluUSA
  4. 4.Laboratoire de Glaciologie et Geophysique de l’EnvironnementDomaine UniversitaireSaint-Martin-d’HèresFrance
  5. 5.Observatoire de ParisMeudonFrance

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