The dust environment at Titan

To explain the observed abundances of CO2 in Titan's atmosphere, a relatively high water deposition into the atmosphere needs to be invoked due to the importance of H2O photolysis in CO2 production. A Likely source of H2O is icy dust particles from space. This paper considers the direct dust input to Titan's atmosphere from the interplanetary environment, and also ejecta particles from micrometeoroid impacts with the icy satellites Hyperion, Iapetus and Phoebe. It is found that the Likely mass influx to Titan is 10(-16) to 10(-15) kg m(-2) s(-1). This mass influx is an order of magnitude too low to explain the observed levels of CO2 in Titan's atmosphere in the context of a recent photochemical model. This leads one to speculate as to the likelihood of one large impact to Titan in the recent past; i.e., that the atmosphere is not in equilibrium but is currently losing CO2.