Further Analyses of the 433eros Global Lineament Map

Introduction: The observed presence of grooves on Eros can be interpreted as being solely due to faulting resulting from the transmission of impact shock waves [1]. However, early studies found two large-scale lineations on Eros (Callisto Fossae and Rahe Dorsum) to be coplanar with a large flat region (the southern " facet ") on one end of the asteroid [2]. This CF-RD-SF plane was interpreted as indicative of a pre-existing structure throughout most of the asteroid, consistent with a fabric inherited from a parent body. A global database of all Eros lineaments (Fig. 1) was recently constructed [3] to better understand the global distribution of these features and thus understand more about the interior structure of the asteroid. Over two thousand linear features, ranging up to tens of kilometers in length, were mapped from 180 high resolution (5-11 m/p) NEAR Multi-Spectral Imager images of Eros [3]. It is possible that those sets of linear features on Eros that formed by a common creation mechanism are either co-planar or describe a series of parallel planes. Because the linear features are mapped directly onto the Eros shape model they have a three dimensional component and can be modeled to define planes that cut through the asteroid. We determined the unit normal , or pole, of the plane described by each individual lineation [2, 3]. We compared the poles of the linea-tions in each set grouped by observed orientation to determine if they are in fact similarly oriented or if the visual identification was confused by the non-spherical shape of the asteroid. The mapped lineations have been grouped into sets according to location and orientation; many different sets of lineaments were identified [3]. Radial Lineation Sets: Some of the lineations are clearly related to specific impact craters; at the time of writing lineations have been identified radial to 13 craters [3]. Given their proximity and orientation relative to the craters it seems most likely that these linea-ments were formed as a direct result of the impact event. Other Lineation Sets of Impact Origin: The most distinct set of lineations on Eros (Set 1, Fig. 2) is found aligned roughly with the prime meridian of the asteroid [3]. Several of these 143 lineations are up to 10's of kilometers long. The orientation of the linea-ments is consistent with the pattern expected from fragmentation due to impact on the long side of an ellipsoid target …