Baland, Rose-Marie ; Yseboodt, Marie ; Rivoldini, Attilio ; Van Hoolst, Tim

published in Icarus, 291 (2017)

Abstract: Mercury is expected to deviate from the classical Cassini state since this state is defined for a uniformly precessing rigid planet. We develop an extended Cassini state model that includes the variations (or nutations) in obliquity and deviation induced by the slow precession of the pericenter. The model also describes the constant shift over time in mean obliquity and deviation associated with the short-periodic tidal deformations of Mercury, characterized by the tidal love number k2 and by the ratio k2/Q of the tidal Love number over the tidal quality factor, respectively. This model is then used to interpret Mercury's orientation, including the deviation from the classical Cassini state, in terms of parameters of Mercury's interior.

DOI: 10.1016/j.icarus.2017.03.020
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Funding: PRODEX/PRODEX/PRODEX