2015/03/24 by W. B. McKinnon · 2 citations
Physics and Astronomy · Biochemistry, Genetics and Molecular Biology · #Astro and Planetary Science #Planetary Science and Exploration #Geomagnetism and Paleomagnetism Studies #Enceladus #Hydrostatic equilibrium #RADIUS #Geology #Polar #Shell (structure) #Saturn #Hydrostatic pressure #Physics #Astrobiology #Geophysics #Astrophysics #Materials science #Astronomy #Planet #Mechanics
paper · pdf · doi:10.1002/2015gl063384
openalex publication_date 2015/03/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Abstract Enceladus's degree 2 gravity, determined by Cassini, is nominally nonhydrostatic to 3σ ( J 2 / C 22 = 3.38–3.63, as opposed to 10/3). Iess et al. (2014) interpret this in terms of a hydrostatic interior (core) and isostatic (not hydrostatic) floating ice shell. Enceladus's rapid (1.37 d) synchronous spin and tide distorts its shape substantially, though, enough that the predicted hydrostatic J 2 / C 22 is not 10/3 but closer to 3.25. This leads to the following revision to the internal picture of Enceladus, compared with Iess et al.: (1) the satellite's core is somewhat smaller and slightly denser (190 km radius and 2450 kg/m 3 ); (2) the compensation depth (shell thickness) of the global (degree 2) ice shell is ≈ 50 km, rather close to the base of the modeled ice + water layer; and (3) the compensation depth (shell thickness) beneath the South Polar Terrain (from J 3 ) remains shallower (thinner) at ≈ 30 km, independent of but influenced by the degree 2 solution.