New Lunar Crater Production Function Based on High-Resolution Images

The lunar crater production function describes the general pattern of the size-frequency distribution of craters on the lunar surface, and it is the foundation of the surface dating method via crater counting. In addition, the lunar crater production function has been extended to other celestial bodies and used to analyze the meteorite flux of the inner solar system. The basic process of establishing the lunar crater production function is to map in an ideal way the primary craters in different geological units, and then to normalize all of the corresponding size-frequency distributions using a mathematical model. Currently, the most widely used lunar crater production functions have been established based on the images acquired in the last century. However, now they can be refined with newly obtained high-resolution images. In this research, we mapped all of the primary craters in 13 regions on the lunar surface with the images acquired using the narrow angle camera and wide angle camera onboard the Lunar Reconnaissance Orbiter, and then we fitted the lunar crater production function with a polynomial. The resultant new lunar crater production function is largely comparable with the previous results, and the difference is mainly at the large diameter end. We analyzed the uncertainty of model fitting as well as the difference in the crater measurements and demonstrated the reliability of the new production function. It is expected to refine the lunar surface dating models, which can provide more accurate information on the impact rate in related studies.