The Uppsala-DLR Trojan Survey of the Preceding Lagrangian Cloud

Abstract.

The Trojan population is considered to be very numerous but a reliable estimate of the total number of objects librating around the Jupiter Lagrangian points is still missing. Furthermore, the true size distribution of the smaller Trojans is largely unexplored. The ESO Schmidt telescope was used during the apparitions in 1996, 1997 and 1998 to search for Trojan asteroids by covering a large region of the sky centered on the preceding Lagrangian point, L4. The Schmidt films were visually inspected shortly after the observations to identify Trojan candidates. Additional positions of these candidates were secured with follow-up observations with the Bochum telescope. During the September 1996 survey, which is nearly complete down to a limiting V magnitude of about 20, we detected almost 400 suspected Trojans, the large majority of which are new discoveries. An estimate of the total number of Trojans based on our still preliminary result from the observation of 1996, indicates a population smaller by a factor three with respect to previous studies (Shoemaker et al., 1989).