Permanent shadow in simple craters near the lunar poles

Abstract

An analysis of simple craters in the lunar polar regions has produced new values for the minimum amount of permanent shadow in these areas, 7500 km2 and 6500 km2, for the north and south pole respectively. These values were obtained by conducting illumination simulations of realistically shaped simple craters, <20 km in diameter, to investigate the size and latitudinal extent of permanently shadowed regions near the lunar poles. Craters as far as 20° from the pole still contain significant amounts of permanent shadow. Larger simple craters have slightly more relative permanent shadow than smaller craters. Seasonal effects are independent of crater size and latitude, with a crater having 15% more of its interior shadowed during a lunar day in winter than in summer.