HR: 0830h
AN: G41B-0036    [PDF]
TI: Mars Nutation Resonance Due To Free Inner Core Nutation
AU: Defraigne, P
EM: p.defraigne@oma.be
AF: Royal Observatory of Belgium, Av Circulaire, 3, Brussels, 1180 Belgium
AU: Rivoldini, A
EM: a.rivoldini@oma.be
AF: Royal Observatory of Belgium, Av Circulaire, 3, Brussels, 1180 Belgium
AU: * Van Hoolst, T
EM: t.vanhoolst@oma.be
AF: Royal Observatory of Belgium, Av Circulaire, 3, Brussels, 1180 Belgium
AU: Dehant, V
EM: v.dehant@oma.be
AF: Royal Observatory of Belgium, Av Circulaire, 3, Brussels, 1180 Belgium
AB: The rotational normal modes of the planet Mars are computed using a numerical approach. We determine the associated resonances in the nutations induced by the external gravitational forcing from the Sun, Phobos and Deimos. In particular, the influence of a possible solid inner core inside a liquid core is investigated. A normal mode associated with the inner core, the Free Inner Core Nutation (FICN), is computed as well as the associated resonance effects in the nutations. For a small inner core, before the eutectic composition of the outer core is reached, the FICN effect on nutation is generally negligible. For a large inner core it can be very important, and for some nutations it can greatly decrease the resonance effect of the classical Free Core Nutation. Using future observations of Mars nutation resonances, expected from the NEtlander Ionosphere and Geodesy Experiment (NEIGE) foreseen for the mission NetLander, it will therefore be possible to get information about the inner core of Mars.
DE: 1227 Planetary geodesy and gravity (5420, 5714, 6019)
DE: 5450 Orbital and rotational dynamics
SC: Geodesy [G]
MN: 2003 Fall Meeting