Thermal evolution of Kuiper belt objects, with implications for cryovolcanism

Steven Desch, Jason C. Cook, T. C. Doggett, Simon B. Porter

Research output: Contribution to journalArticle

60 Scopus citations

Abstract

We investigate the internal thermal evolution of Kuiper belt objects (KBOs), small (radii <1000 km), icy (mean densities < 2500 kg m- 3) bodies orbiting beyond Neptune, focusing on Pluto's moon Charon in particular. Our calculations are time-dependent and account for differentiation. We review evidence for ammonia hydrates in the ices of KBOs, and include their effects on the thermal evolution. A key finding is that the production of the first melt, at the melting point of ammonia dihydrate, ≈ 176   K, triggers differentiation of rock and ice. The resulting structure comprises a rocky core surrounded by liquids and ice, enclosed within a >100-km thick undifferentiated crust of rock and ice. This structure is especially conducive to the retention of subsurface liquid, and bodies the size of Charon or larger (radii >600 km) are predicted to retain some subsurface liquid to the present day. We discuss the possibility that this liquid can be brought to the surface rapidly via self-propagating cracks. We conclude that cryovolcanism is a viable process expected to affect the surfaces of large KBOs including Charon.

Original languageEnglish (US)
Pages (from-to)694-714
Number of pages21
JournalIcarus
Volume202
Issue number2
DOIs
StatePublished - Aug 1 2009

Keywords

  • Charon
  • Ices
  • Spectroscopy
  • Thermal histories
  • Trans-neptunian objects
  • Volcanism

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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