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Stardust Shape Models of Comet Wild 2, V2.1 (PDS)

NSSDCA ID: PSSB-00133

Availability: Archived at NSSDC, accessible from elsewhere

Description

This data set contains the basic tri-axial ellipsoid shape model and the detailed plate model of comet 81P/Wild 2 derived from the Stardust NAVCAM images taken around the time of closest approach. The tri-axial ellipsoid model is 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

The detailed plate shape model is 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-V2.1 on volume SA0701_0001. The data are available online at:

http://pdssbn.astro.umd.edu/holdings/sdu-c-navcam-5-wild2-shape-model-v2.1/

This data set supercedes PSSB-00070.

Alternate Names

  • SDU-C-NAVCAM-5-WILD2-SHAPE-MODEL-V2.1

Disciplines

  • Planetary Science: Small Bodies
  • Planetary Science: Geology and Geophysics

Additional Information

Spacecraft

Experiments

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

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. Donald E. BrownleeData ProviderUniversity of Washingtonbrownlee@astro.washington.edu
Dr. Tony FarnhamGeneral ContactUniversity of Marylandfarnham@astro.umd.edu
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