The unique geomorphology and structural geology of the Haulani crater of dwarf planet Ceres as revealed by geological mapping of equatorial quadrangle Ac-6 Haulani

Abstract

The dwarf planet Ceres has been explored by NASA's Dawn spacecraft with the goal of characterizing its geology, mineralogy, topography, shape, and internal structure. One outcome of this exploration is the production of geologic maps, meant to unveil the geologic history of Ceres. In this paper, we present the geologic map of the Ac-6 Haulani quadrangle (Lat. 22°S-22°N, Long. 0°-72°E) based on Low Altitude Mapping Orbit (LAMO) (∼35 m/pixel) data supplemented with color and spectral data, as well as a digital terrain model from the High Altitude Mapping Orbit (HAMO) (∼135 m/pixel, vertical accuracy of about 10 m). The 34 km diameter Haulani crater is one of the youngest features on Ceres and the most prominent one in the quadrangle. Haulani was formed on a topographical transition in north-south direction and shows a complex morphology with a variety of lobate flows and tectonic features. Multiple cracks and depressions around the crater indicate the failure of subsurface material. These were likely formed by the subsidence of material due to the instability of the subsurface. The mapping of Ac-6 Haulani suggests that Ceres is built up of layers with different material properties. We propose that Ceres has a solid crust and a variable ice-rich subsurface consistent with previous and recent models of Ceres' interior.