In this paper we present results on the size distribution of circumstellar disks in the Trapezium cluster as measured from HST/WFPC2 data .
Direct diameter measurements of a sample of 135 bright proplyds and 14 silhouettes disks suggest that there is a single population of disks well characterized by a power-law distribution with an exponent of - 1.9 \pm 0.3 between disk diameters 100–400 AU .
For the stellar mass sampled ( from late G to late M stars ) we find no obvious correlation between disk diameter and stellar mass .
We also find that there is no obvious correlation between disk diameter and the projected distance to the ionizing Trapezium OB stars .
We estimate that about 40 % of the disks in the Trapezium have radius larger than 50 AU .
We suggest that the origin of the Solar system ’ s ( Kuiper belt ) outer edge is likely to be due to the star formation environment and disk destruction processes ( photoevaporation , collisions ) present in the stellar cluster on which the Sun was probably formed .
Finally , we identified a previously unknown proplyd and named it 266-557 , following convention .