Numerical simulations of convection and melt migration in Io’s mantle
Abstract
Io is the most volcanically active body in the solar system. The Laplace resonance with Europa and Ganymede maintains Io’s high eccentricity, which leads to tidal heating in Io’s mantle. The extensive volcanism on Io’s surface and the detection of an induced magnetic field at Io [1] suggest that the tidal heating is so extreme that it partially melts Io’s mantle. Previous modeling of convection in Io’s mantle has shown that convection alone is not enough to produce the current observed high heat flux if Io is in thermal equilibrium [2]. However, if tidal heating partially melts Io’s mantle, this magma will buoyantly rise through the solid grains and erupt to the surface carrying heat from the interior with it. This is known as the heat pipe mechanism of planetary heat loss. Io is currently the only body in our solar system losing heat mainly through this mechanism. However, it may have been relevant to other bodies in our solar system earlier in their history, and it could be relevant to extrasolar planets experiencing high internal heating rates. We study this process in the context of Io using the mantle convection code StagYY, which includes the formation, migration, and eruption of magma. Although previous studies of Io’s mantle have considered melt migration [3] or convection [e.g. 4], this is the first study to consider both processes. We find that Io does have a partially molten mantle, and that it loses two orders of magnitude more heat through volcanic eruptions than through conduction through its stagnant lid, which exemplifies the heat pipe mechanism of heat loss. The rate of heat loss from the volcanic eruptions is on average equal to the tidal heating rate we assume, but it oscillates around this value, which suggests that measurements of Io’s heat flux are not necessarily representative of its average heat loss over longer time scales.[1] Khurana K. K. et al. (2011) Science, 332, 1186-1189. [2] Moore W. B. (2003) J. Geophys. Res., 108, E8, 15-1. [3] Moore, W. B. (2001) Icarus, 154, 548-550. [4] Tackley, P. J. (2001) Icarus, 149, 79-93.
- Publication:
-
AAS/Division for Planetary Sciences Meeting Abstracts #46
- Pub Date:
- November 2014
- Bibcode:
- 2014DPS....4641105E