The cooling rate of a liquid shell in Titan's interior

Research areas:
Year:
1996
Authors:
Journal:
ICARUS
Volume:
123
Number:
1
Pages:
101-112
Month:
September
ISSN:
0019-1035
BibTex:
Abstract:
Models describing the evolution of the primordial liquid layer in
Titan's interior are presented using parameterized models. These models
incorporate recent experimental data on the ammonia water phase diagram
in the range {[}100 MPa-1 GPa] and recently published creep laws for ice
I. Just after accretion, the thickening of the outer ice I layer is
achieved by conduction. It seems likely that this outer shell becomes
thick enough for solid-state convection to start about 200 myr after
accretion. The temperature in the ice I outer shell cannot be larger
than the melting temperature of the NH3-H2O liquid at the interface
between the liquid layer and the ice I shell. As a result, the
temperature in the ice I layer is much smaller than the melting
temperature for ice I and the viscosity is too large to yield very
vigorous convection and rapid cooling of the satellite. Moreover, this
study suggests that the decay of the radioactive element content in the
silicate rich inner core of the satellite keeps heating the core for 3
byr after the core overturn. If present after accretion, a liquid layer
is likely to exist at the present time in Titan's interior. The
thickness of the liquid layer does not vary much with time and its value
depends only on the initial amount of ammonia. (C) 1996 Academic Press,
Inc.