Tidal dissipation, surface heat flow, and figure of viscoelastic models of Io

Segatz, M.; Spohn, Tilman; Ross, M. N.; Schubert, G.

doi:10.1016/0019-1035(88)90001-2

Cited by 250 publications

(311 citation statements)

References 38 publications

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“…The upper and lower boundaries correspond to the base of a crust/lithosphere and the top of a relatively highviscosity, chemically denser mantle, respectively, and are thus assumed to be rigid and isothermal (top) or zero flux (bottom). Because of variations in suflhce temperature and likely variations in crust/lithosphere thickness the upper (isothermal) boundary condition is only an approximation, but it is thought to be reasonable because in rigid lid convection the top of the convecting region is defined by a particular viscosity hence isotherm [Moresi and Solomatov, 1995;Solomatov, 1995]; furthermore, the effects of the huge horizontal variation in internal heating rate are likely to swamp any effects due to horizontal variation in thermal boundary condition An aspect ratio of 15 is chosen for most of the cases, which for an asthenosphere depth of 100 km approximately corresponds to 1/8 the distance around Io, which is the smallest distance between minima and maxima of the asthenosphere tidal dissipation function [Segatz et al, 1988]. The actual effective aspect ratio could be much higher than this if the asthenosphere is thinner, so larger aspect ratios are also considered.…”

Section: Model and Methodsmentioning

confidence: 99%

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Convection in Io's asthenosphere: Redistribution of nonuniform tidal heating by mean flows

Tackley¹

2001

J. Geophys. Res.

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Section: Model and Methodsmentioning

confidence: 99%

“…The focusing of dissipation near the upper and lower boundaries [Segatz et al, 1988] Time-dependent solutions are obtained using the finite volume multigrid code STAG3D described elsewhere [Tackley, 1993[Tackley, , 1996a …”

Section: Cpkmentioning

confidence: 99%

Convection in Io's asthenosphere: Redistribution of nonuniform tidal heating by mean flows

Tackley¹

2001

J. Geophys. Res.

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“…The value for Mercury is Q Mercury < 190, and for Venus it is Q Venus < 17 (Goldreich and Soter, 1966). Observations of Io imply Q Io < 100 (Peale et al, 1979;Segatz et al, 1988), while the Moon lies at Q Moon = 26.5 -1 (Dickey et al, 1994). These measurements indicate a similar order of magnitude for the tidal dissipation function of all desiccated bodies in the Solar System.…”

Section: E4 Tidal Response In Celestial Bodiesmentioning

confidence: 74%

“…Although a large atmosphere can play a significant role in the evolution of terrestrial planets (Correia and Laskar, 2003), we ignore their effect here due to the large number of unknowns for an exoplanet. In real bodies, Q is a function of the bodies' rigidity l, viscosity g, and temperature T (Segatz et al, 1988;Fischer and Spohn, 1990). A comprehensive tidal model would couple the orbital and structural evolution of the bodies since small perturbations in T can result in large variations in Q (Segatz et al, 1988;Mardling and Lin, 2002;Efroimsky and Lainey, 2007).…”

Section: E4 Tidal Response In Celestial Bodiesmentioning

confidence: 99%

“…In real bodies, Q is a function of the bodies' rigidity l, viscosity g, and temperature T (Segatz et al, 1988;Fischer and Spohn, 1990). A comprehensive tidal model would couple the orbital and structural evolution of the bodies since small perturbations in T can result in large variations in Q (Segatz et al, 1988;Mardling and Lin, 2002;Efroimsky and Lainey, 2007). Moreover, tidally generated heat will not necessarily be transported to the surface quickly.…”

Section: E4 Tidal Response In Celestial Bodiesmentioning

confidence: 99%

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Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

et al. 2013

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Traditionally, stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here, we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at highenough levels to induce a runaway greenhouse for a long-enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets ''Tidal Venuses'' and the phenomenon a ''tidal greenhouse.'' Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e., with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable, as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. We simulated the evolution of hypothetical planetary systems in a quasi-continuous parameter distribution and found that we could constrain the history of the system by statistical arguments. Planets orbiting stars with masses < 0.3 M Sun may be in danger of desiccation via tidal heating. We have applied these concepts to Gl 667C c, a *4.5 M Earth planet orbiting a 0.3 M Sun star at 0.12 AU. We found that it probably did not lose its water via tidal heating, as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for noncircular orbits. In the appendices we review (a) the moist and runaway greenhouses, (b) hydrogen escape, (c) stellar mass-radius and mass-luminosity relations, (d) terrestrial planet mass-radius relations, and (e) linear tidal theories.

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Structural and tidal models of Titan and inferences on cryovolcanism

Sohl

Solomonidou

Wagner

et al. 2014

J. Geophys. Res. Planets

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Titan, Saturn's largest satellite, is subject to solid body tides exerted by Saturn on the timescale of its orbital period. The tide‐induced internal redistribution of mass results in tidal stress variations, which could play a major role for Titan's geologic surface record. We construct models of Titan's interior that are consistent with the satellite's mean density, polar moment‐of‐inertia factor, obliquity, and tidal potential Love number k2 as derived from Cassini observations of Titan's low‐degree gravity field and rotational state. In the presence of a global liquid reservoir, the tidal gravity field is found to be consistent with a subsurface water‐ammonia ocean more than 180 km thick and overlain by an outer ice shell of less than 110 km thickness. The model calculations suggest comparatively low ocean ammonia contents of less than 5 wt % and ocean temperatures in excess of 255 K, i.e., higher than previously thought, thereby substantially increasing Titan's potential for habitable locations. The calculated diurnal tidal stresses at Titan's surface amount to 20 kPa, almost comparable to those expected at Enceladus and Europa. Tidal shear stresses are concentrated in the polar areas, while tensile stresses predominate in the near‐equatorial, midlatitude areas of the sub‐ and anti‐Saturnian hemispheres. The characteristic pattern of maximum diurnal tidal stresses is largely compliant with the distribution of active regions such as cryovolcanic candidate areas. The latter could be important for Titan's habitability since those may provide possible pathways for liquid water‐ammonia outbursts on the surface and the release of methane in the satellite's atmosphere.

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Tidal dissipation, surface heat flow, and figure of viscoelastic models of Io

Cited by 250 publications

References 38 publications

Convection in Io's asthenosphere: Redistribution of nonuniform tidal heating by mean flows

Convection in Io's asthenosphere: Redistribution of nonuniform tidal heating by mean flows

Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

Structural and tidal models of Titan and inferences on cryovolcanism

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