3 research outputs found
Relaxation of Wobbling Asteroids and Comets. Theoretical Problems. Perspectives of Experimental Observation
A body dissipates energy when it freely rotates about any axis different from
principal. This entails relaxation, i.e., decrease of the rotational energy,
with the angular momentum preserved. The spin about the major-inertia axis
corresponds to the minimal kinetic energy, for a fixed angular momentum. Thence
one may expect comets and asteroids (as well as spacecraft or cosmic-dust
granules) stay in this, so-called principal, state of rotation, unless they are
forced out of this state by a collision, or a tidal interaction, or cometary
jetting, or by whatever other reason. As is well known, comet P/Halley,
asteroid 4179 Toutatis, and some other small bodies exhibit very complex
rotational motions attributed to these objects being in non-principal states of
spin. Most probably, the asteroid and cometary wobble is quite a generic
phenomenon. The theory of wobble with internal dissipation has not been fully
developed as yet. In this article we demonstrate that in some spin states the
effectiveness of the inelastic-dissipation process is several orders of
magnitude higher than believed previously, and can be measured, by the
presently available observational instruments, within approximately a year
span. We also show that in some other spin states both the precession and
precession-relaxation processes slow down considerably. (We call it
near-separatrix lingering effect.) Such spin states may evolve so slowly that
they can mimic the principal-rotation state.Comment: 2 figure