Deviation of the Major Axis of the Inertia Ellipsoid of the Moon from the Direction Toward the Earthстатья
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Дата последнего поиска статьи во внешних источниках: 28 сентября 2017 г.
Аннотация:Abstract—It is known from observations that the center of mass of the Moon does not coincide with the
geometric center of its figure, and the line connecting these two centers is not aligned with the direction
toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the
axis of the inertia ellipsoid of theMoon to the South of the direction toward the Earth is analyzed. A system
of five linear differential equations describing the physical libration of the Moon in latitude is considered,
and these equations are derived using a new vector method taking into account perturbations from the
Earth. The characteristic equation of this system is obtained, and all five oscillation frequencies are found.
Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equation
is stationary and represents a previously unknown additional motion of the rotational axis of the Moon in a
cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the
angular-velocity vector is in the positive direction (counter-clockwise), with the period T3 = 27.32 days.
On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a
stationary inclination of the major axis of the inertia ellipsoid of the Moon to the South (for an observer on
Earth), making it possible to explain one component of the observed deviation of the center of mass of the
Moon fromthe direction toward the Earth. The opening angle of the quasi-precession cone is approximately
0.834.