Polygonal impact craters on mercury

•This study confirms earlier papers about the existence of PICs on Mercury.•The assumed context that PICs are an integral part of all impact craters is verified.•A number of 33 craters out of 291 named craters was identified as PICs (11.3%).•The PICs show the morphology of complex craters with terraced rims.•PICs are lying in a range of diameters between 65 and 240 km (mean 120 km).

The existence of polygonal impact craters (PICs) on Mercury is confirmed by this study, which was performed by analyzing 291 named impact craters greater than 12 km in diameter, photographed by the spacecraft Mariner 10 and MESSENGER. All 15 quadrangles of Mercury were scanned for polygonal impact craters with at least two straight rim segments. A resulting total number of 33 PICs out of the 291 named impact craters is in accordance with the expectation of 10–15% out of all impact craters. Calculations were performed on the number of PICs per quadrangle, on the distribution of polygonal impact craters on the surface, on the distribution of diameters, on the mean values of diameters, and the values of the angles between straight rims and the results plotted. The distribution of PICs per quadrangle does not follow any pattern, but is roughly proportional to the number of impact craters. The diameter range of the PICs lies between 65 and 240 km, on average the value is about 120 km. Some topics need further studies – the lack of small PICs, the interrelations of PICs and geological environments, and the irregular distribution of PICs on the surface showing large empty areas.