Data Set Information
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| DATA_SET_NAME |
PLATE SHAPE MODEL OF ASTEROID LUTETIA V1.0
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| DATA_SET_ID |
RO-A-OSINAC/OSIWAC-5-LUTETIA-SHAPE-V1.0
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| NSSDC_DATA_SET_ID |
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| DATA_SET_TERSE_DESCRIPTION |
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| DATA_SET_DESCRIPTION |
Data Set Overview : This data set presents the detailed plate shape model of asteroid 21 Lutetia,as derived by L. Jorda, R. Gaskell, M. Kaasalainen and B. Carry from theimages that were obtained by the Rosetta spacecraft around the time of itsclosest approach to the asteroid, and from lightcurve data. Twelve differentversions are included to provide a variety of surface resolution. Additionalinformation about the model can be found in Sierks et al., 'Images ofAsteroid 21 Lutetia: A remnant planetesimal from the early solar system',Science 334, 487, 2011 [SIERKSETAL2011B] The Rosetta spacecraft reached its closest approach to Lutetia on10 July 2010 15:45 UT at a distance of 3168.2 km. The Optical, Spectroscopic,and Infrared Remote Imaging System (OSIRIS) instrument (including both theNarrow Angle Camera (NAC) and the Wide Angle Camera (WAC)) obtainedbody-resolved images starting 9.5 hours before closest approach andcontinuing until 18 minutes after. Images covered more than 50% of thesurface, with spatial scales up to 60 m/pix. The shape model presented here was developed by Laurent Jorda et al. from thecombination of two different techniques: Stereophotoclinometry, using 60 ofthe NAC and WAC images, was used to model the surface illuminated and visiblein the Rosetta images. The rest of the surface was constrained using theinversion of 50 photometric lightcurves and the contours of adaptive opticsimages (Carry et al., 'Physical properties of the ESA Rosetta target asteroid(21) Lutetia. II. Shape and flyby geometry', Astron & Astrphys. 523, A942010 [CARRYETAL2010]). The orientation of the spin axis, derived as part of the solution, is suchthat the North (positive) pole points to a right ascension of 51.8+/-0.4 degand a declination of +10.8+/-0.4 deg (J2000). The body's coordinate system was defined with the +Z axis in the direction ofthe spin axis and the prime meridian (+X axis) is defined to pass through thecenter of the crater Lauriacum, located at ~38 deg latitude (see the fileLUTETIA-ROTATION.PDF in the DOCUMENTS directory). The +Y axis completes theright-hand coordinate system. The body center is not exactly coincident withits center of gravity, but the offset is within the uncertainties derived forthe surface positions. The mass of Lutetia was estimated from Radio Science Investigation (Patzoldet al., 'Asteroid 21 Lutetia: Low Mass, High Density', Science 334, 491, 2011[PATZOLDETAL2011]) to be (1.700+/-0.017)e18 kg. Combining this with thevolume computed from the shape model, gives a bulk density 3400+/-300 kg/m^3. PLATE MODEL The model is given in the standard PDS vertex/triangular plate format (seeplate_shape_definition.txt in the documents directory) with dimensions incartesian coordinates. The models consist of the following LUTETIA_003M_CART.WRL - 1572866 vertices forming 3145728 triangular plates LUTETIA_002M_CART.WRL - 793099 vertices forming 1586194 triangular plates LUTETIA_780K_CART.WRL - 392257 vertices forming 784510 triangular plates LUTETIA_380K_CART.WRL - 191312 vertices forming 382620 triangular plates LUTETIA_240K_CART.WRL - 122066 vertices forming 244128 triangular plates LUTETIA_190K_CART.WRL - 94864 vertices forming 189724 triangular plates LUTETIA_098K_CART.WRL - 49142 vertices forming 98280 triangular plates LUTETIA_048K_CART.WRL - 23894 vertices forming 47784 triangular plates LUTETIA_025K_CART.WRL - 12265 vertices forming 24526 triangular plates LUTETIA_012K_CART.WRL - 5979 vertices forming 11954 triangular plates LUTETIA_006K_CART.WRL - 2914 vertices forming 5824 triangular plates LUTETIA_003K_CART.WRL - 1483 vertices forming 2962 triangular plates The data are presented with VRML wrappers that allow the files to bedisplayed with existing VRML viewers that are freely available (e.g., INSTANTPLAYER, OCTAGA, CORTONA, etc.) Different camera angles have been embedded inthe WRL file to display the nuclues from all of the principal axisdirections, with the 'headlight' illumination. Note that the capabilities ofdifferent viewers may limit the ability to display some or all of theseviewpoints. Look for 'cameras' or 'navigation' items in the menus. SURFACE DISCONTINUITY The shape model contains a flaw in the surface that produces a notable jumpin elevation around the body. This discontinuity is the seam between the twoportions of the model constrained with the different derivation techniques(stereophotoclinometry and lightcurve analysis). There are also a few'holes' in the face that are discontinuous. These defects are illustrated inthe images LUTETIA_SEAM.PNG and LUTETIA_HOLES.PNG in the DOCUMENTS directory. TABLE: Shape Model Characteristics Surface Area: 33331 km^2 Volume: 5.0e5 +/- 0.4e5 km^3 Mean diameter: 98 +/- 2 km (diameter of sphere of equivalent volume) Radius range: 33.4 to 64.7 km Dimensions along the principal axes of inertia: A: (121 +/- 1) km B: (101 +/- 1) km C: ( 75 +/- 13) km Axis orientation: RA: 51.8 +/- 0.4 deg Dec: +10.8 +/- 0.4 deg Rotation Period: 8.168270 +/- 0.000001 hr Author------The descriptions in this file were written by Tony Farnham, based oninformation from Laurent Jorda and [SIERKSETAL2011B].
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| DATA_SET_RELEASE_DATE |
2013-08-01T00:00:00.000Z
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| START_TIME |
1965-01-01T12:00:00.000Z
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| STOP_TIME |
N/A (ongoing)
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| MISSION_NAME |
INTERNATIONAL ROSETTA MISSION
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| MISSION_START_DATE |
1995-03-01T12:00:00.000Z
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| MISSION_STOP_DATE |
N/A (ongoing)
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| TARGET_NAME |
21 LUTETIA
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| TARGET_TYPE |
ASTEROID
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| INSTRUMENT_HOST_ID |
RO
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| INSTRUMENT_NAME |
OSIRIS - NARROW ANGLE CAMERA
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| INSTRUMENT_ID |
OSINAC
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| INSTRUMENT_TYPE |
FRAME CCD REFLECTING TELESCOPE
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| NODE_NAME |
Small Bodies
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| ARCHIVE_STATUS |
LOCALLY_ARCHIVED
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| CONFIDENCE_LEVEL_NOTE |
Confidence Level Overview : Lightcurve/adaptive optics analysis, which provided the primary constraintson the portions of the body unseen by Rosetta, was good to within 2 km of theStereophotoclinometry technique in regions where both techniques could beapplied. This provides confidence that the unseen portions of the model arevalid. Review :The plate model was peer reviewed on 5 March 2013.
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| CITATION_DESCRIPTION |
Farnham, T.L., SHAPE MODEL OF ASTEROID 21 LUTETIA, RO-A-OSINAC/OSIWAC-5-LUTETIA-SHAPE-V1.0, NASA Planetary Data System, 2013.
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| ABSTRACT_TEXT |
Shape model of asteroid 21 Lutetia, as derived from the Rosetta images obtained around the time of closest approach. Twelve different versions of the model, at different resolutions, are given.
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| PRODUCER_FULL_NAME |
Tony L. Farnham
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| SEARCH/ACCESS DATA |
SBN Comet Website
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