Thermal evolution of Kuiper belt objects, with implications for cryovolcanism

详细信息    查看全文

• 作者：Steven J. Desch ; Jason C. Cook ; T.C. Doggett ; Simon B. Porter
• 关键词：Charon ; Ices ; Spectroscopy ; Thermal histories ; Trans-neptunian objects ; Volcanism
• 刊名：Icarus
• 出版年：2009
• 出版时间：August 2009
• 年：2009
• 卷：202
• 期：2
• 页码：694-714
• 全文大小：524 K

文摘

We investigate the internal thermal evolution of Kuiper belt objects (KBOs), small (radii <1000 km), icy (mean densities ) 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.