KPL/PCK

Comet Churyumov-Gerasimenko -- RSOC Solution
===========================================================================

 
Version and Date
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     Version 0.1 -- January 26, 2011 -- M. Kueppers, SRE-OSR/ESA 
                    Corrected spin axis direction

     Version 0.0 -- September 9, 2010 -- J. Vazquez, PSA, SRE-OS/ESA
     
 
 
Organization
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     The sections of this file are as follows.
 
     Introductory Information:
 
         --   Version description
 
         --   Disclaimer
 
         --   Sources
 
     Pck Data:
 
         --   Orientation constants for Comet 67P/Churyumov-Gerasimenko
 
         --   Radii for Comet 67P/Churyumov-Gerasimenko
 
 
Version description
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     This is a PCK containing values for the pole orientation, 
     rotation period and shape obtained from [2] and [3].
     
 
Disclaimer
--------------------------------------------------------
 
     This constants file may not contain the parameter values that you
     prefer. Note that this file may be readily modified by you or
     anyone else. PSA suggests that you inspect this file visually
     before proceeding with any critical or extended data processing.
 
     PSA requests that you update the version section if you modify
     the file.
 
 
Sources
--------------------------------------------------------
 
     The sources for the constants listed in this file are:
 
        1) ESA Science and Technology Server, Rosetta area,
           http://sci.esa.int/science-e/www/object/index.cfm?
           fobjectid=34849

        2) Hubble Space Telescope observations of the nucleus and inner
           coma of comet 67P/Churyumov-Gerasimenko, Lamy et al., A & A 458,
           669, June 2006
        
        
        3) Comet 67P/Churyumov-Gerasimenko at a large heliocentric distance,
           Tubiana et al., A & A 490, 377, 2008

        4) Lamy et al., Rosetta book, P. 21ff, 2009.

Orientation constants for Comet Churyumov-Gerasimenko.
------------------------------------------------------
 
     The inertial reference frame for these constants is J2000; this is
     the default reference frame for PCK orientation data.
 
     The epoch of the constants is J2000; this is Julian ephemeris date
     (JED) 2451545.0.
 
     The NAIF integer code for Comet Churyumov-Gerasimenko is 1000012. See 
     the NAIF_IDs required reading for further information on NAIF integer
     codes.
 
     According to [2] the comet pole direction is specified by the 
     following right ascension (RA) and declination (DEC):

        RA  =  40 deg.
        DEC =  70 deg.

    

     The W1 term was set to correspond to the period of 12.7 hours, taken 
     from [3], and the W0 term is arbitrarily set to 0.
     
     \begindata
 
        BODY1000012_POLE_RA             = (  40.0        0.0         0.0 )
        BODY1000012_POLE_DEC            = (  70.0        0.0         0.0 )
        BODY1000012_PM                  = (   0.0      680.315       0.0 )
 
     \begintext


Radii for Comet 67P/Churyumov-Gerasimenko 
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     The radii provided in the keyword below correspond to the 
     following comet shape

          a/b/c = 2.28km/1.905km/1.72km

     provided in [2].
 
     \begindata
 
        BODY1000012_RADII               = ( 2.28  1.905  1.72 )
 
     \begintext


Albedo Values for Comet 67P/Churyumov-Gerasimenko
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     The value for the albedo is provided in [4].

     \begindata

        BODY1000012_ALBEDO  = 0.04

     \begintext