KPL/PCK

Asteroid Psyche P_constants (PcK) SPICE kernel file
===========================================================================
 
     By: Ryan Park  -- 10-APR-2018


Organization
--------------------------------------------------------

     The sections of this file are as follows.

     Introductory Information:

         --   Version description

         --   Disclaimer

         --   Sources

     Pck Data:

         --   Orientation constants for asteroid Psyche

         --   Radii for asteroid Psyche

     Frames data:

         --   PSYCHE_FIXED frame definition
 
 
Version Description
--------------------------------------------------------

     This file was created on April 10, 2018.

     This is a preliminary PCK containing draft values for the pole
     direction, prime meridian location, rotation period and shape
     (from [1].)


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. NAIF suggests that you inspect this file visually
     before proceeding with any critical or extended data processing.

     NAIF requests that you update the ``by line'' and date if you
     modify the file.


Sources
--------------------------------------------------------

     The sources for the constants listed in this file are:

        1) Shepard, Michael K., et al. ``Radar observations and shape
           model of asteroid 16 Psyche'' ICARUS 281, 2017.
           http://dx.doi.org/10.1016/j.icarus.2016.08.011

           The Psyche coordinate system is shown in the ecliptic frame
           (EMO2000) in Shepard et al. (2017), which was rotated into
           the equatorial frame (EME2000) and truncated at the 0th
           decimal place since the uncertainty is > 1 deg.

           The prime meridian value (W0) is what was used to fit the
           radar shape in Shepard et al. (2017) and the value was
           provided via email.

        2) Baer, James and Chesley, Steve R., ``Simultaneous Mass
           Determination for Gravitationally Coupled Asteroids'' ASTRON.
           J. 154, 2017. https://doi.org/10.3847/1538-3881/aa7de8


Orientation constants for asteroid Psyche
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     The rotation constants below are from [1].

     \begindata
 
        BODY2000016_POLE_RA    = (  34.00    0.0       0.0 )
        BODY2000016_POLE_DEC   = (   6.00    0.0       0.0 )
        BODY2000016_PM         = ( 266.75  2059.12942677   0.0 )

     \begintext


Radii for asteroid Psyche
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     The radii values below are from [1].

     \begindata
 
        BODY2000016_RADII      = ( 139.5  116.0  94.5 )
 
     \begintext


GM for asteroid Psyche
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     The GM value below is from [2].

     \begindata

        BODY2000016_GM         = (  1.53  )
 
     \begintext


PSYCHE_FIXED Frame Definition
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     The primary location of this frame definition is in the Psyche
     mission FK file. It is included in this PCK solely for
     convenience.

     The Psyche fixed frame is defined in the same as any other PCK
     frame:

        *  +Z along the North pole;

        *  +X toward the prime meridian;

        *  +Y completes the right hand frame;

        *  the origin of this frame is at the center of the body.

     The orientation of this frame is computed by evaluating
     corresponding rotation constants provided in this PCK file.

   \begindata

      FRAME_PSYCHE_FIXED               =  2000016
      FRAME_2000016_NAME               = 'PSYCHE_FIXED'
      FRAME_2000016_CLASS              =  2
      FRAME_2000016_CLASS_ID           =  2000016
      FRAME_2000016_CENTER             =  2000016
      OBJECT_2000016_FRAME             = 'PSYCHE_FIXED'

   \begintext

End of PCK file.