THE DISTRIBUTION OF ASTEROID SIZES AND ITS SIGNIFICANCE

Eleven years ago, Hughes (Mon. Not. R. astr. Soc. 199, 1149, 1982) gav e the size distribution of 740 asteroids. This has now been updated us ing 1778 known asteroidal diameters. The mass distribution index of th e large main-belt asteroids is now found to be 2.09+/-0.10. A power la w relationship has been obtained between the perihelion distance and t he diameter of the smallest known asteroid in any group of asteroids t hat have a specific range of perihelion distance. This has been used, in conjunction with the size distribution function, to produce a ''cor rected'' histogram of asteroidal perihelion distances in which the rel ative significance (in number) of the Trojan asteroids has been increa sed dramatically. It is also concluded that the mass of the asteroid b elt, M(A) (g), is given by log M(A) = 26.21 (+1.4, -1.0).