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 language | English (US) |
---|---|
Pages (from-to) | 694-714 |
Number of pages | 21 |
Journal | Icarus |
Volume | 202 |
Issue number | 2 |
DOIs | |
State | Published - Aug 1 2009 |
Keywords
- Charon
- Ices
- Spectroscopy
- Thermal histories
- Trans-neptunian objects
- Volcanism
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science