SCATTERING ELLIPSES FOR AN EXTENDED CATALOGUE OF RECENT IMPACT SITES ON MARS

Abstract

Over the past decades, about 1.400 recent meteoroid impact sites have been discovered on Mars, which include single craters and crater scattering fields, with crater sizes up to 70 m. Due to the more rarefied (in comparison with Earth) atmosphere of Mars, meteoroids entering the atmosphere are less destroyed. Nevertheless, about half of them fragment in the atmosphere and form crater clusters. Study of crater clusters on Mars reveals details of cosmic body fragmentation that cannot be detected in terrestrial conditions. Earlier it was suggested that the description of a cluster by an ellipse allows ones to estimate the parameters of the meteoroid trajectory, the entry angle and azimuth. In this paper, scattering ellipses for 105 clusters are considered. Independent estimates of the flight direction were made for 89 of these clusters using crater ejecta; in 54–56 cases (depending on the method of the ellipse constructing), the crater ejecta are oriented along the main axis of the scattering ellipse; the flight direction coincides in 29–32 cases. For the remaining clusters, crater ejecta are oriented along the minor axis of the scattering ellipse, counterintuitively.