  In 2003, we initiated a long-term adaptive optics campaign to study the orbit
of various main-belt asteroidal systems. Here we present a consistent solution
for the mutual orbits of four binary systems: 22 Kalliope, 45 Eugenia, 107
Camilla and 762 Pulcova. With the exception of 45 Eugenia, we did not detect
any additional satellites around these systems although we have the capability
of detecting a loosely-bound fragment (located at 1/4 x RHill) that is ~40
times smaller in diameter than the primary. The common characteristic of these
mutual orbits is that they are roughly circular. Three of these binary systems
belong to a C-"group" taxonomic class. Our estimates of their bulk densities
are consistently lower (~1 g/cm3) than their associated meteorite analogs,
suggesting an interior porosity of 30-50% (taking CI-CO meteorites as analogs).
22 Kalliope, a W-type asteroid, has a significantly higher bulk density of ~3
g/cm3, derived based on IRAS radiometric size measurement. We compare the
characteristics of these orbits in the light of tidal-effect evolution.
