Coagulation Code for Planet Formation

Coagulation is growth by collision and merger

Statistical approach to inelastic collisions
Fragmentation algorithm for collision outcomes
Fokker-Planck approach to elastic collisions

Coagulation codes have several advantages

Essential for 1015 or more planetesimals
Calculate evolution of small planets accurately
Calculate collisional cascade

Coagulation codes also have some disadvantages

Fail when most of the mass in a few large objects
Cannot predict final mass of planet
Cannot model formation of gas giant planets

Multiannulus particle-in-a-box method

Treats planetesimals as statistical ensemble
Particles in all annuli interact
Fragmentation + Gas drag + Poynting-Robertson drag
Code is parallel to run on modern supercomputer

We also calculate the evolution of dust grains

Separate treatment of small particles
Synthesize luminosity evolution and model images

We have extensively tested the code

Code reproduces previous published results

We used the bybrid code to calculate the formation of Earth-like planets.
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