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Stardust Shape Models of Comet Wild 2 (PDS)


Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)

Time span: 2004-01-02 to 2004-01-02


This data set has been superceded by PSSB-00133 (PDS ID SDU-C-NAVCAM-5-WILD2-SHAPE-MODEL-V2.1), see:

This data set contains the two shape models (versions 1 and 2) of comet 81P/Wild 2 as derived from the Stardust images taken around the time of closest approach. Version 1 is a tri-axial ellipsoid model fit to the limb and terminator in the 72 images of Wild 2 taken during the Stardust encounter. The images were taken using a broadband filter and had a resolution of 57 microrad/pixel. As only half the surface was illuminated during the flyby there is some uncertainty in extrapolating to the unilluminated side. The basic ellipsoid axial dimensions were determined to be 1.65 x 2.00 x 2.75 km +/-0.05 km. A body-fixed coordinate system was established with the short axis as the rotation pole and the long axis defining the prime meridian. The data are held in a table with an accompanying descriptive label. The full table is reproduced below, the second number is the one-sigma uncertainty:

major semi-axis 2.75 0.05 km intermediate semi-axis 2.00 0.05 km minor semi-axis 1.65 0.05 km Pole RA 110. 3. deg Pole DEC -13. 3. deg Arg Prime Meridian 155. 3. deg

This is PDS ID SDU-C-NAVCAM-5-WILD2-SHAPE-MODEL-V1.0 held on CD Volume SAO505_0001. It is available online at:

Version 2 is a detailed plate shape model derived from the same set of images as the version 1 model. Pairs of these images were used to generate stereo views of the comet and to determine the cartesian XYZ coordinates of points on the surface. The model consists of 6432 points forming 12514 plates, covering the portions of the nucleus that were both illuminated and visible during the encounter (about 50% of the total surface).

Four versions of the plate model are included here. The primary version (WILD2_CART_VIS.TAB) is given in Cartesian coordinates based on a body-centered system. A second version (WILD2_PLAN_VIS.TAB) is given in planetocentric coordinates, with distances given from the center of the ellipsoid. In both of these versions, only the visible and illuminated portions of the nucleus are included. Two additional versions of the model (WILD2_CART_FULL.TAB and (WILD2_PLAN_FULL.TAB, respectively) again provide the shape models in Cartesian and planetocentric coordinates, but include full coverage of the surface of the nucleus. In these versions, the non-visible portions of the surface are represented by the best-fitting ellipsoid.

This is PDS ID SDU-C-NAVCAM-5-WILD2-SHAPE-MODEL-V2.0 held on CD Volume SAO603_0001. It is available on-line at:

Alternate Names



  • Planetary Science: Small Bodies

Additional Information



Questions and comments about this data collection can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Mr. Thomas C. DuxburyGeneral ContactNASA Jet Propulsion

Selected References

  • Duxbury, T. C., et al., Comet 81P/Wild 2 size, shape, and orientation, J. Geophys. Res., 109, E12S02, doi:10.1029/2004JE002316, 2004.
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