On 5 March 2004, SwRI researches Bill Merline, Peter Tamblyn, and Clark Chapman, along with their collaborators, announced the discovery of yet another asteroid satellite. This team, which has pioneered the field of groundbased detection of asteroid satellites, has discovered 13 of the 19 known satellites orbiting asteroids in the main asteroid belt (between Mars and Jupiter). To assist their groundbased search, they are using the Hubble space Telescope (HST) to look for satellites around fainter asteroids. In the last year alone, Merline's team (including the participation of Dan Durda and David Nesvorny of SwRI in the HST program, has discovered 6 satellites (35% of those known) using sophisticated groundbased telescopes equipped with adaptive optics and the Hubble Sapce Telescope. Such satellites are created when two asteroid collide. The study of asteroid satellites is yielding new clues about the mechanics of collisions between objects in space, which clearly shaped much of the solar system, including the Earth and our own Moon. Further, these satellites allow us to measure directly the density of the asteroids, from which we can learn about the composition and internal structure of the asteorids.
The text of the IAUC circular can be found here.
Discovery image (below) of the satellite of asteroid (4674) Pauling, taken at the Very Large Telescope of the European Southern Observatory (ESO) on Cerro Paranal, Chile, on March 4, 2004. The observations were acquired by Bill Merline and Peter Tamblyn of SwRI, plus several other European and US participants. The companaion is about 1.5 miles across and it orbits the main asteroid (which is 5 miles across) once every 50 days. The objects are separated by about 150 miles. It is an example of a new type of binary that is made when two asteroids collide in a huge, catastrophic collision. Such collisions are being modelled at SwRI by Durda and colleagues.