Lunar and Planetary Science XLVIII (2017) 1943.pdf

PRELIMINARY 8-COLOR MAP OF THE SHAKESPEARE QUADRANGLE ON MERCURY. N. Bott1, A. Doressoundiram1, D. Perna1, F. Zambon2, C. Carli2 and F. Capaccioni2, 1LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot (5 place Jules Janssen, 92195 Meudon, France; [email protected]), 2Istituto di Astrofisica e Planetologia Spaziali-INAF, Roma, Italy.

Introduction: After three flybys, the MErcury Sur- Methods: To produce the Shakespeare quadrangle face, Space Environment, GEochemistry and Ranging 8-colors map, we used the software ISIS provided by (MESSENGER) spacecraft orbited Mercury for four USGS. We first downloaded and imported MESSEN- years until April 2015, providing the first complete GER raw data of the Shakespeare quadrangle into ISIS map of its surface thanks to the Mercury Dual Imaging format. We georeferenced the data by using the SPICE System (MDIS). The Wide-Angle Camera (WAC) ob- kernel for each image. We then performed a radiomet- served Mercury with 12 different filters, from 433.2 nm ric calibration to remove, for instance, the current dark to 1012.6 nm. Since the images from the filters at and the flat field, and we projected the data using an 698.8, 947.0 and 1012.6 nm are not enough to cover equirectangular projection. Afterwards, we applied the the quadrangle, we use data from 8 of the 11 filters Hapke photometric correction [4,5], testing several set available (479.9, 558.9, 628.8, 433.2, 748.7, 996.2, of parameters. The photometric correction is used to 898.8 and 828.4 nm) for the scientific analysis, while report the data at standard illumination condition, such filter at 700 nm was used only for calibration. as those frequently used in laboratory (ph=30°, i=30°, For the mapping, Mercury's surface has been subdi- e=0°). Therefore, we coregistered the images to obtain vided into 15 quadrangles. Some of these quadrangles an 8-color mosaic of Shakespeare quadrangle. have already been mapped [1,2]. Here we present a Preliminary Results and Future Works: Here, we preliminary 8-color mapping on the Shakespeare quad- show two preliminary maps of Shakespeare, which rangle, which extends from 22.5° to 65° in latitude and cover ~5% of its surface. Figure 2 is a map at one from 180° to 270° in longitude (Figure 1). This 8-color wavelength, whereas Figure 3 is a Red-Green-Blue map will be compared to the planetary geological map (RGB) map. The goal is to do the same work for the of the same quadrangle to evidence the correlation be- whole quadrangle. Applying particular techniques of tween the geological units of Shakespeare, as defined analysis, such as RGB color combinations [6,7], we by [3], and the spectral properties and discuss the dif- can emphasize difference in composition. The results ferences. will be presented and discussed. This preliminary work is part of an international Once 8-color cube of Shakespeare quadrangle will collaboration between Italian, English and French be completed, we will work on the spectral characteris- teams, whose aim is to map the Mercury's surface inte- tics of this quadrangle. This spectral analysis will no- grating photo-interpreted units and spectral units. The tably help us to investigate which kind of space weath- objectives of these works are 1) to integrate color units ering occurs on Mercury's surface. with morpho-stratigraphic ones for this quadrangle and 2) to define regions of interest in support to the SIM- BIO-SYS instrument onboard the future BepiColombo mission, thus participating to its observational strategy.

Fig. 1. Location of the Shakespeare quadrangle (green rec- tangle) with respect to the other quadrangles and of the por- Fig. 2. Monochrome map (996.2 nm) of a part of the Shake- tion mapped in Figures 2 and 3 (red rectangle). speare quadrangle. Latitude: 22.5° to 32.5°; longitude: 180° to 200°. Lunar and Planetary Science XLVIII (2017) 1943.pdf

Fig. 3. Red-Green-Blue (Red=996.2 nm, Green=748.7 nm, Blue=433.2 nm) map of a part of the Shakespeare quadran- gle. Latitude: 22.5° to 32.5°; longitude: 180° to 200°.

References: [1] Galluzzi V. et al. (2016) Journal of Maps, 12, 227-238. [2] Zambon F. et al. (2016) Geophysical Re- search Abstracts, 18, EGU2016-16909. [3] Guzzetta L. et al. (accepted) Journal of Maps. [4] Domingue D. L. et al. (2015) Icarus, 257, 477-488. [5] Domingue D. L. et al. (2016) Icarus, 268, 172-203. [6] Denevi B. W. (2009) Science, 324, 613-618. [7] Kerber L. et al. (2011) Planetary and Science Space, 59, 1895-1909 Acknowledgments: This work was partly sup- ported by the Centre National d'Études Spatiales (CNES).