An asteroid pair consists of two unbound objects with almost identicalheliocentric orbital elements that were formed when a single "rubble pile"asteroid failed to remain bound against an increasing rotation rate. Modelssuggest that the pairs' progenitors gained the fast rotation due to the YORPeffect. Since it was shown that the spin axis vector can be aligned by the YORPeffect, such a behavior should be seen on asteroid pairs, if they were indeedformed by the described mechanism. Alternatively, if the pairs were formed by acollision, the spin axes should have a random direction and small or youngbodies might have a tumbling rotation. Here I apply the lightcurve inversion method on self-obtained photometricdata, in order to derive the rotation axis vectors and shape models of theasteroid pairs 2110, 3749, 5026, 6070, 7343 and 44612. Three asteroids resultedwith polar-directed spin axes and three objects with ambiguous results. Inaddition, the secondary member 44612 presents the same sense of rotation as itsprimary member 2110, and its spin is not tumbling. Finally, I use a rotationalfission model, based on the assumption of an angular momentum conservation, andmatch it to the measured spin, shape, and mass ratio parameters in order toconstrain the density of the primary members in the pairs. Using this method,low density values that are expected from a "rubble pile" are derived. Allthese results lead to the conclusion that the disruption of these asteroidpairs was most likely the outcome of the YORP effect that spun-up "rubble pile"asteroids.
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