Print Email Facebook Twitter The Tides of Enceladus' Porous Core Title The Tides of Enceladus' Porous Core Author Rovira Navarro, M. (TU Delft Astrodynamics & Space Missions; NIOZ Royal Netherlands Institute for Sea Research; University of Arizona) Katz, Richard F. (University of Oxford) Liao, Yang (Woods Hole Oceanographic Institution) van der Wal, W. (TU Delft Astrodynamics & Space Missions; TU Delft Physical and Space Geodesy) Nimmo, Francis (University of California) Date 2022 Abstract The inferred density of Enceladus' core, together with evidence of hydrothermal activity within the moon, suggests that the core is porous. Tidal dissipation in an unconsolidated core has been proposed as the main source of Enceladus' geological activity. However, the tidal response of its core has generally been modeled assuming it behaves viscoelastically rather than poroviscoelastically. In this work, we analyze the poroviscoelastic response to better constrain the distribution of tidal dissipation within Enceladus. A poroviscoelastic body has a different tidal response than a viscoelastic one; pressure within the pores alters the stress field and induces a Darcian porous flow. This flow represents an additional pathway for energy dissipation. Using Biot's theory of poroviscoelasticity, we develop a new framework to obtain the tidal response of a spherically symmetric, self-gravitating moon with porous layers and apply it to Enceladus. We show that the boundary conditions at the interface of the core and overlying ocean play a key role in the tidal response. The ocean hinders the development of a large-amplitude Darcian flow, making negligible the Darcian contribution to the dissipation budget. We therefore infer that Enceladus' core can be the source of its geological activity only if it has a low rigidity and a very low viscosity. A future mission to Enceladus could test this hypothesis by measuring the phase lags of tidally induced changes of gravitational potential and surface displacements. Subject enceladushydrothermalinteriorporoviscoelasticitytides To reference this document use: http://resolver.tudelft.nl/uuid:0f14ec1a-ca62-4fe1-a0bf-7e9b39c8124d DOI https://doi.org/10.1029/2021JE007117 ISSN 2169-9097 Source JRG Planets, 127 (5) Part of collection Institutional Repository Document type journal article Rights © 2022 M. Rovira Navarro, Richard F. Katz, Yang Liao, W. van der Wal, Francis Nimmo Files PDF JGR_Planets_2022_Rovira_N ... s_Core.pdf 2.2 MB Close viewer /islandora/object/uuid:0f14ec1a-ca62-4fe1-a0bf-7e9b39c8124d/datastream/OBJ/view