The asteroid pair was once assumed to be a single body, called Antiope, orbiting the sun in the outer parts of the asteroid belt between the orbits of Mars and Jupiter. Pulcova was the third asteroid observed to have a moon. It is possible that a few more moonlets might emerge from more sophisticated analysis of the data we have collected. The astronomers expect to find still more configurations and surprises as the survey continues. Asteroids were once thought to be single, mountain-like chunks of material, perhaps smashed into 'flying rubble piles' by occasional collisions among themselves.
Asteroidal companions provide vital information about asteroids that has been difficult to obtain.
Until now, the best measurements of asteroid mass and density came from deflections of spacecraft flying past an asteroid. But an asteroidal satellite, or twin, is a body whose trajectory is deflected by the asteroid's gravity and forced to orbit around it. The revolution time provides a measure of the body's mass, hence density. Using these techniques, Merline's team earlier found that Eugenia, Pulcova, and Antiope are light bodies, with less density than rocks, even though their sufaces appear dark like rock. Adaptive optics enable ground-based telescopes to observe asteroids and other small points of light with the same clarity as the Hubble Space Telescope.