  We describe in this work a thorough study of the physical and orbital
characteristics of extensively observed main-belt and Trojan binaries, mainly
taken from the LAOSA (Large Adaptive Optics Survey of Asteroids, Marchis et
al., 2006c) database, along with a selection of bifurcated objects.
Dimensionless quantities, such as the specific angular momentum and the primary
spin rate, are computed and discussed for each system. They suggest that these
asteroidal systems might be the outcome of rotational fission or mass shedding
of a parent body presumably subjected to an external torque.
  One of the most striking features of separated binaries composed of a large
primary (Rp > 100 km) with a much smaller secondary (Rs < 20 km) is that they
all have total angular momentum of 0.27. This value is quite close to the
Maclaurin-Jacobi bifurcation (0.308) of a spinning fluid body. Alternatively,
contact binaries and tidally locked double asteroids, made of components of
similar size, have an angular momentum larger than 0.48. They compare
successfully with the fission equilibrium sequence of a rotating fluid mass. In
conclusion, we find that total angular momentum is a useful proxy to assess
internal structure of such systems.
