Title: Comparison between the nutations of the planet Mars and the nutations of the Earth
Authors: Van Hoolst, Tim # ×
Issue Date: 2000
Publisher: D. Reidel Pub. Co.
Series Title: Surveys in geophysics vol:21 pages:89-110
Abstract: The nutations of the planets Mars and Earth are investigated and compared. A
large number of interior structure parameters are involved in the nutation
computations. The comparison between the observations and the computations
provides several constraints on these parmeters and
therefore allows a better understanding of the physics of the interior of the
planet. For the Earth, the high precision of the observations of the nutations
has led to a very good determination of interior properties of the planet. For
Mars, observations of nutations are not yet available, and we review how the
amplitude of the Martian nutations depends on the hypotheses considered
for its interior. Although Mars is very similar to the Earth,
its interior is not well known;
for example, we don't know
if its core is liquid or solid. Only if the core is liquid,
the Free Core Nutation (FCN) normal mode exists and can alter the nutations
which are close to the resonance. From the observed geoids, it is known that
both planets are not in hydrostatic equilibrium. The departure is larger for
Mars than for the Earth, and consequently, the implication of considering a
convective mantle instead of a mantle in hydrostatic equilibrium described by
Clairaut's equation for the initial equilibrium state of the planet is larger
on the Martian nutations than on the Earth nutations. The consequences of the
uncertainty in the core dimensions are also examined and shown to be of a very
high influence for Mars if the core is liquid, due to the potential changes in
the FCN resonance. The influence of the presence of an inner core, which is
known to exist for the Earth, could be more important for Mars than for the
Earth if the inner core is large. Due to the presence of Tharsis on Mars, the
triaxiality of this planet has, additionally, larger effects than on
ISSN: 0169-3298
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Institute of Astronomy
× corresponding author
# (joint) last author

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