The trans-Neptunian objects are the icy bodies beyond the orbit of Neptune.
They have a high fraction (∼30%) of >100km low inclination bodies
that exist as binaries, with a few found to have nearly equal size and widely
separated components. Such binaries may be the result of excess angular momentum in the gravitational collapse of a pebble cloud, formed by the streaming instability. This mechanism can be modelled by N-body integration of a slowly rotating cloud of particles, in the Hill approximation. We replicate the findings of Nesvorny et al. 2010, confirming that the model efficiently produces wide, equal sized binaries. We then identify some areas for improvement. With our simulations, we are trying to replicate the collisional behavior of a high number density of pebbles with a limited number of computational particles, via use of a particle radius inflation factor. We attempt to derive this factor with a simple mass accretion model, and present arguments that question the validity of
this assumption. We have also assessed how momentum changes for a collision
between two computational particles, compared to the case of many collisions
between the large number of pebbles that they represent. It is shown that the
latter is analogous to Brownian motion, with a random walk of the resultant
momentum. Therefore, we investigate the effects of these momentum considerations on our simulations as alternatives to the idea of size inflation presented by Nesvorny.