Space Research & Planetary Sciences Division Web Site

Illustration of the fly-by of 21 Lutetia by Rosetta using OSIRIS NAC images.

On 10 July 2010, Rosetta made a close fly-by (3168 km from the target) of asteroid 21 Lutetia. 3D models now show a highly irregular shape ((126 ± 1) × (103 ± 1) × (95 ± 13) km3).  The spacecraft passed the asteroid at 14.995 km/s. The phase angle of the approach was 7.7 degrees. The OSIRIS imaging system produced some superb images of the target (see below and Thomas et al., 2012). We are currently working on modeling the impact of the latest event (which contributed most to the structure of the Baetica region).

We have demonstrated that ejecta deposition from the largest impact in the north polar crater cluster matches features observed using Rosetta’s OSIRIS camera. Crater erasure via the seismic shock from the impact was shown to be less significant and inconsistent with observation. The velocity field lines ~50 s after impact exhibit a qualitative correlation with surface lineament orientation (Jutzi et al., 2013), which provides a plausible explanation for these remarkable phenomena on small bodies.

 

Figure 1
Figure 2
Figure 3

Figure 1: Region definition on Lutetia.

Figure 2: This is a tricky image. The heavily enhanced regions are actually in shadow. But the scattered from illuminated regions is bright enough to give a measureable signal. And OSIRIS is sensitive enough to pick it up and reveal structure.

Figure 3: Features and landslides within the North Polar Crater Cluster. Lots of fun stuff.

 

Figure 4
Figure 5
Figure 6

Figure 4: The Baetica-Noricum boundary. Note the abrupt change in crater density across the boundary. The top left is a much younger surface.

Figure 5: Marvellous set of lineaments in the Noricum region. Some of these structures are 80 km long.

Figure 6: Some of the lineaments cut crater rims (A). Parallel sets of lineaments are also seen. The interiors of craters also show signs of tectonics.

 

Relevant Publications:

Thomas, N., C. Barbieri, H.U. Keller, P. Lamy, H. Rickman, R. Rodrigo, H. Sierks, K.P. Wenzel, G. Cremonese, L. Jorda, M. Küppers, S. Marchi, F. Marzari, M. Massironi, F. Preusker, F. Scholten, K. Stephan, M.A. Barucci, S. Besse, S. Fornasier, O. Groussin, S.F. Hviid, D. Koschny, E. Kührt, E. Martelleto, R. Moissl, C. Snodgrass, C. Tubiana, and J.-B.Vincent, (2012), The geomorphology of (21) Lutetia: Results from the OSIRIS imaging system onboard ESA’s Rosetta spacecraft, Planetary and Space Science, 66, 96-124, doi:10.1016/j.pss.2011.10.003.

Jutzi, M., N. Thomas, W. Benz, M.R. El Maarry, L. Jorda, E. Kührt, F. Preusker, (2013), The influence of recent major crater impacts on the surrounding surfaces of (21) Lutetia, Icarus, 226, 89-100, doi:10.1016/j.icarus.2013.05.022.

Space Research & Planetary Sciences Division Web Site