Description of the Shape model of Hartley 2, as derived from the DIXI flyby data. by Peter Thomas Latitude-longitude model of 103P/Hartley 2. Hartley2_2012_plan.tab This data set presents the latitude, longitude, radius shape model of comet 103P/Hartley 2, as derived from the images of the comet obtained by the Deep Impact spacecraft around the time of closest approach on November 4, 2010. Additional information about the model can be found in Thomas et al. "Shape, Density, and Geology of the Nucleus of Comet 103P/Hartley 2" Icarus 222, 550-558 (2012). The model is presented in body-centered planetocentric coordinates, with vertices at intervals of 2 degrees in both latitude and longitude. The radial distance is given in kilometers and ranges from a minimum of 0.31 km to a maximum 1.26 km. The shape is such that it is not well represented by a triaxial ellipsoid. The center of figure is about 5 meters from the coordinate origin (19.6 North, 240.4 East). Each row of this table contains data for one vertex, in the form of the latitude, longitude and distance from the center in a planetocentric coordinate system. The row also contains a flag denoting whether the point comes from a region well constrained by control points ('1'; these have relative errors of largely less than 20 meters), or a region constrained by limb coordinates ('2', these have higher uncertainties because of the ambiguity in location of the limb position.), or not closely constrained ('3'; areas more than 0.11 km from either of the above types of control, and may have errors of 30-40 meters). Data are from the Deep Impact Extended Investigation. The DI spacecraft and its instruments are described in A'Hearn et al. (2005) and Hampton et al. (2005). Most useful MRI data were obtained at <1600 km range (16 meters/pixel). A few HRI images were useful out to ranges of ~2500 km. An important characteristic of this comet is its complex rotation (Belton et al., 2012) which limits any mapping convention that would be tied to rotation. This rotation includes a primary period, increasing through encounter, and a roll about the long axis, with a decreasing period. Most useful mapping data were obtained within an interval when a simplified model of rotation predicts that the object orientation changed by ~0.6 degrees. The routine mapping was done with a simple rotation model that introduces relative position errors of ~0.3 degrees between ends of the object. Determination of the shape and accurate relative positioning of the images relies upon stereo control points. Limb coordinates provide additional constraints on the shape, but have an ambiguity on where the surface is intersected by the line of sight. Cartesian shape model of Hartley 2 Hartley2_2012_cart.wrl A second version of the model was derived from the planetocentric version. In this version, the vertices are presented in cartesian coordinates. The X axis is defined in the direction of the intersection of the equator and the prime meridian, the Z axis lies along the positive pole and the Y axis completes the right-hand coordinate system. Image mosaic of Hartley 2. hartley2_8ppd_imagemosaic.png Images from The MRI and HRI were map projected using the derived shape model. Projection is simple cylindrical. The prime meridian has been placed at a dark feature, part of which is a block shadow, in the middle of the lit half of the comet nucleus. The scale is 8 pixels per degree. Images have been moderately high-pass filtered, and manually stretched to remove some of the image-to-image differences in brightness. A labeled version is hartley2_8ppd_imagemosaic_1.png Images used for the maps of Hartley 2 hv0342149157 hv0342149157_5004008_001 hv0342149184 hv0342149184_5004012_001 hv0342149203 hv0342149203_5004015_001 hv0342149224 hv0342149224_5004018_001 hv0342149403 hv0342149403_5006002_001 hv0342149423 hv0342149423_5006004_001 hv0342149440 hv0342149440_5006007_001 mv0342149244 mv0342149244_5004027_001 mv0342149264 mv0342149264_5004032_001 mv0342149283 mv0342149283_5004042_001 mv0342149288 mv0342149288_5004044_001 mv0342149298 mv0342149298_5004046_001 mv0342149303 mv0342149303_6000002_001 mv0342149307 mv0342149307_5004051_001 mv0342149312 mv0342149312_5004052_001 mv0342149317 mv0342149317_5004053_001 mv0342149322 mv0342149322_5004054_001 mv0342149327 mv0342149327_5004056_001 mv0342149342 mv0342149342_6000003_001 mv0342149352 mv0342149352_5004062_001 mv0342149362 mv0342149362_5004064_001 mv0342149372 mv0342149372_5004066_001 Prime meridian view of Hartley 2. hartley2_pm_view.png A view of the comet with superposed latitude-longitude grid at 10 degree spacing is shown with the Prime Meridian denoted. The view is similar to that obtained near closest approach from about 10 degrees South, 10 degrees East (~image mv0342149307_5004051_001). Principal direction views of Hartley 2 hartley2views_gridded.png Five views of the shape model with image map overlain are shown. The viewpoints are labeled for each panel. 0 degrees North, 180 degrees East is not shown as there is little illuminated area visible from this direction.