Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso


  • Stefano Mottola
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_5198-1


(253) Mathilde is a dark, primitive Main Belt asteroid classified as a C type. The body, which is approximately 50 km in size, was the third asteroid to be visited by spacecraft when the Discovery space probe NEAR Shoemaker flew by in 1997 on its route to NEA Eros. Pre-encounter ground-based observations performed during the 1995 apparition have allowed an unusually long rotation period in excess of 17 days to be determined. In addition, those observations have detected multiple periodicities in the body’s lightcurve, which have been interpreted as the signature of free precession. Although NEAR Shoemaker could only image one hemisphere of the body, due to its slow rotation and to the fast flyby geometry, the bulk density of the body could be estimated to 1.3 g/cm3. This value, which is lower than the density of analog carbonaceous chondritic meteorites, implies comparatively high porosity. The visible surface of the body is characterized by several very large impact...


Bulk Density Rotation Period Impact Event Free Precession Impact Crater 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.German Aerospace Center (DLR)Institute of Planetary ResearchBerlinGermany