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Impactor Flux and Cratering on the Pluto-Charon System

We study the impactor flux and cratering on Pluto and Charon due to the collisional evolution of Plutinos. Plutinos are those trans-Neptunian objects located at 39.5 AU, in the 3:2 mean motion resonance with Neptune. To do this, we develop a statistical code that includes catastrophic collisions and cratering events, and takes into account the stability and instability zones of the 3:2 mean motion resonance with Neptune. We proposes different initial populations that account for the uncertainty in the size distribution of Plutinos at small sizes. Depending on the initial population, our results indicate the following. The number of D > 1 km Plutinos streaking Pluto over 3.5 Gyr is between 1271 and 5552. For Charon, the number of D > 1 km Plutino impactors is between 354 and 1545. The number of D > 1 km craters on Pluto produced by Plutinos during the last 3.5 Gyr is between 43076 and 113879. For Charon, the number of D > 1 km craters is between 20351 and 50688.The largest Plutino impactor onto Pluto has a diameter between 17 and 23 km, which produces a craterwith a diameter of 31 - 39 km. The largest Plutino impactor onto Charon has a diameter between 10 and 15 km, which produces a crater with a diameter of 24 - 33 km. We test if 2 Pluto-sized objects are assumed in the 3:2 Neptune resonance, then the total number of Plutino impactors both onto Pluto as Charon with diameters D > 1 km is a factor of 1.6 - 1.8 larger if considering 1 Pluto-sized object. Given the dynamical structure of the trans-Neptunian region, it is necessary to study in detail the contribution of all the potential sources of impactors on the Pluto-Charon system, to obtain the main contributor and the whole production of craters. Then, we will be able to contrast those studies with observations which will help us to understand the geological processes and history of the surface of those worlds.