Modeling crater populations on Venus and Titan

We apply the model with the same parameter values to Titan to predict crater populations under differing assumptions of impactor populations that reflect present conditions. We assume that the impactors (comets) are made of 50% porous ice. Predicted crater production rates are ≈190 craters (109yr)-1. The smallest craters on Titan are predicted to be ≈2km in diameter, and ≈5 crater fields (109yr)-1 are expected. If the impactors are composed of solid ice (density 0.92gmcm-3), crater production rates increase by ≈70% and the smallest crater is predicted to be ≈1.6km in diameter. We give cratering rates for denser comets and atmospheres 0.1 and 10 times as thick as Titan's current atmosphere. We also explicitly address leading-trailing hemisphere asymmetries that might be seen if Titan's rotation rate were strictly synchronous over astronomical timescales: if that is the case, the ratio of crater production on the leading hemisphere to that on the trailing hemisphere is ≈4:1.