Population and Size Distribution of Small Jovian Trojan Asteroids

We present a study of Jovian Trojan objects detected serendipitously during the course of a sky survey conducted at the University of Hawaii 2. 2-meter telescope. We used a 8192 x 8192 pixel charge-coupled device (CCD) mosaic to observe 20 deg² at locations spread over the L4 Lagrangian swarm and reached a limiting magnitude V = 22. 5 mag (50% of maximum detection efficiency). Ninety-three Jovian Trojans were detected with radii 2 - 20 km (assumed albedo 0. 04). Their differential magnitude distribution has a slope of 0. 40 +/- 0. 05 corresponding to a power law size distribution index 3. 0 +/- 0. 3 (1-sigma). The total number of L4 Trojans with radii > 1 km is of order 1. 6 x 10⁵ and their combined mass (dominated by the largest objects) is ~ 10^-4 M₄₀ₑₓ₇. The bias-corrected mean inclination is 13. 7 +/- 0. 5 deg. We also discuss the size and spatial distribution of the L4 swarm.