We describe a Monte Carlo model that simulates dust migration in a porous cometary nucleus. We present computations for media in which the pore-size distributions are either random or normal; additional computations indicate that media with power-law size distributions behave very similarly to random distributions. We show how the average time to cross the medium varies as a function of porosity and how the structure of the medium varies with time. Implications for the structure of the cometary nucleus are discussed.
- Comet surfaces