This paper reviews coagulation models for planet formation in the Kuiper Belt , emphasizing links to recent observations of our and other solar systems .
At heliocentric distances of 35–50 AU , single annulus and multiannulus planetesimal accretion calculations produce several 1000 km or larger planets and many 50–500 km objects on timescales of 10–30 Myr in a Minimum Mass Solar Nebula .
Planets form more rapidly in more massive nebulae .
All models yield two power law cumulative size distributions , N _ { C } \propto r ^ { - q } with q = 3.0–3.5 for radii r \gtrsim 10 km and N _ { C } \propto r ^ { -2.5 } for radii r \lesssim 1 km .
These size distributions are consistent with observations of Kuiper Belt objects acquired during the past decade .
Once large objects form at 35–50 AU , gravitational stirring leads to a collisional cascade where 0.1–10 km objects are ground to dust .
The collisional cascade removes 80 % to 90 % of the initial mass in the nebula in \sim 1 Gyr .
This dust production rate is comparable to rates inferred for \alpha Lyr , \beta Pic , and other extrasolar debris disk systems .