KPL/PCK

Asteroid Dinkinesh P_constants (PcK) SPICE kernel file
===========================================================================
 
   This text PCK contains rotational and ellipsoidal shape constants
   for asteroid Dinkinesh. 
 
Version and Date
--------------------------------------------------------
 
   Version 1.0 -- November 6, 2023 -- Matt Barnes, NAIF/JPL
 
      This is the first Dinkinesh PCK released for official use by 
      Lucy project. It contains values for the pole direction, rotation 
      period and shape from [1] and [2].
     
 
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 ``Version and Date`` if you modify
   the file.
 
 
Sources
--------------------------------------------------------
 
   The sources for the constants listed in this version of this file
   are:
 
     1) Mottola, Stefano, et al. ``Characterizing Asteroid (152830)
        Dinkinesh in Preparation for the Encounter with the NASA Lucy
        Mission: a Photometric Study'', Monthly Notices of the Royal
        Astronomical Society: Letters, Volume 524, Issue 1, September
        2023, Pages L1–L4, https://doi.org/10.1093/mnrasl/slad066

     2) Email ``Dinky PCK'' from David Kaufmann, SWRI, 2023 August 25.

Orientation constants for asteroid Dinkinesh
--------------------------------------------------------
 
   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 Dinkinesh is 920152830. See the NAIF_IDs
   required reading for further information on NAIF integer codes.
 
   The pole direction, prime meridian location, and rotation period
   in this version are set to the following values from [1]:

      "
         Synodic Period (h)   52.67
      "

   Converting this period to deg/day yields 164.0 deg/day.

   Placeholder values are used for POLE_RA, POLE_DEC values per project
   convention.

   The LONG_AXIS keyword providing the offset between the longest axis
   of the triaxial ellipsoid used to model Dinkinesh and the 
   Dinkinesh prime meridian is not used by SPICE geometry 
   software. It is considered deprecated and provided solely for 
   backwards compatibility.

   Pole RA and DEC are given in degrees, rate W1 in degrees/day.

      \begindata
 
         BODY920152830_POLE_RA   = (    0.0     0.0     0.0  )
         BODY920152830_POLE_DEC  = (  +90.0     0.0     0.0  )
         BODY920152830_PM        = (    0.0   164.0     0.0  )
         BODY920152830_LONG_AXIS = (    0.0                  )
 
      \begintext


Radii for asteroid Dinkinesh
--------------------------------------------------------

   The radii in this version are set based on following values from [1]:

       "
          axial ratio a/b ~ > 1.43
          spherical surface-equivalent diameter between 0.66 and 1.36 km
       "

   Using a value of 1.01 km as the surface-equivalent diameter - the average
   of the ends of the given range - and the value of 1.43 for the axial
   ratio per [2], the following parameters are used to create a prolate
   spheroid representing Dinkinesh:

      Long axis  = 0.634 km
      Short axis = 0.444 km

   Values below are given in km.

      \begindata

         BODY920152830_RADII     = (   0.634    0.444    0.444  )
 
      \begintext

End of PCK file.