MINERALOGICAL ANALYSIS OF THE QUADRANGLES AC-11 SINTANA AND AC-12 TOHARU ON THE DWARF PLANET CERES

Quadrangles Ac-11 and Ac-12 are two of the one of four southern quadrangles of the dwarf planet Ceres. These quadrangles have several craters, notably the large Sintana and Toharu which give the names to the quadrangle. To study the mineralogical composition of this sourthen region we use in particular the data returned by the Visible and InfraRed (VIR) mapping spectrometer onboard Dawn. This hyperspectral data enable a careful mineralogical analysis of the region. In the High-Altitude Mapping Orbit HAMO phase, yielding an average pixel resolution of ~0.38 km, VIR obtained nearly global coverage of the two quadrangles, even if the most southern areas are not fully mapped because the data are affected by bad illumination conditions. We use the maps of the bands 2.7 and 3.06 µm, respectively indicative of the presence and kind of hydrous minerals and ammoniated phyllosilicates. Based on this dataset, some craters stand out compared to the rest of the quadrangle. Notably the craters Tupo, Juling and Kupalo, show smaller band depths with respect the average terrains. Some of them show also bright materials. Similar, but less evident, spectral behavior, is observed in other small craters found in this region. Acknowledgements

This work is supported by the Italian Space Agency (ASI). VIR was funded and coordinated by the Italian Space Agency, with the scientific leadership of the Institute for Space Astrophysics and Planetology, Italian National Institute for Astrophysics, Italy. Support of the Dawn Science, Instrument, and Operation Teams is gratefully acknowledged.