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CONTENTS  : This file provides the ephemeris of the ninth Saturnian satellite: Phoebe


AUTHOR    : J. Desmars


INSTITUTE : SHAO/IMCCE


E-MAIL    : desmars@imcce.fr


REFERENCE : Desmars J, Li S.N., Tajeddine R., Peng Q.Y., Tang Z.H.
	    Phoebe's Orbit from ground-based and space-based observations
	    A&A xxx, pp xxx-xxx, 2013 	

================================================================================
FILES 
-----
- README.txt	: This file
- ph12.dat	: Chebychev polynomia
- r-ph12.f90 	: Fortran subroutines used to compute ephemeris
- test.f90	: Fortran program to test the computation


================================================================================
README FILE:       
------------
This ephemeris of Phoebe is based on a numerical model fitted to the observations dispatched from 1898 to 2012. 
This ephemeris is available  for the period [1875/07/01:2022/06/30] and through Chebychev polynomia (ph12.dat) readable with the Fortran subroutines contained in r-ph12.f90. 


================================================================================
FORTRAN SUBROUTINES
-------------------
header	: Read the header of ph12.dat to load information such as degree
	   of polynomia or period of validity
		Out:	- nc	: degree of polynomia
			- ni	: number of intervals
			- a	: first date of validity
			- b	: last date of validity
				
load 	: Load the coefficients of Chebychev polynomia
		In :	- nc	: degree of polynomia     (given by header)
			- ni	: number of intervals     (given by header)
		Out:	- cf	: coefficients
			- dat	: limit period of intervals

pos_ph12: Compute the position and velocity for a specific date (in TDB)
		In :	- a	: first date of validity  (given by header)
			- b	: last date of validity   (given by header)
			- nc	: degree of polynomia     (given by header)
			- ni	: number of intervals     (given by header)	
			- cf	: coefficients            (given by load)
			- dat	: period of intervals     (given by load)
			- t	: time in Julian Day(TDB) (given by user)
		Out:	- x 	: 6-dimension vector position-velocity 		

================================================================================
UNITS:
------
Positions and velocities are delivered in au and au/day.

================================================================================
EXAMPLE:
---------
Computation of test program should provide:

DJ =  2450000.500
x  =     -0.0565331612828     0.0683539886662     0.0384516012357
v  =      0.0006274381157     0.0005863244731     0.0001848068219
  
DJ =  2450010.500
x  =     -0.0500094770787     0.0738915516615     0.0401187775865
v  =      0.0006760155712     0.0005207212932     0.0001485844868
  
DJ =  2450020.500
x  =     -0.0430380897546     0.0787600402881     0.0414227955219
v  =      0.0007170207018     0.0004526029081     0.0001122122879
  
DJ =  2450030.500
x  =     -0.0356934838269     0.0829369615563     0.0423632094735
v  =      0.0007506989597     0.0003824876405     0.0000758949141
  
DJ =  2450040.500
x  =     -0.0280477753291     0.0864046264541     0.0429414578429
v  =      0.0007772769397     0.0003108203647     0.0000398058905
  
DJ =  2450050.500
x  =     -0.0201709424078     0.0891494848086     0.0431605890901
v  =      0.0007969545986     0.0002379862858     0.0000040948415
  
DJ =  2450060.500
x  =     -0.0121311204687     0.0911615948338     0.0430250573146
v  =      0.0008098999282     0.0001643238889    -0.0000311057595
  
DJ =  2450070.500
x  =     -0.0039949380689     0.0924342165894     0.0425405797986
v  =      0.0008162458227     0.0000901369008    -0.0000656748103
  
DJ =  2450080.500
x  =      0.0041721225095     0.0929635183165     0.0417140493061
v  =      0.0008160884008     0.0000157050494    -0.0000994974835
  
DJ =  2450090.500
x  =      0.0123053506931     0.0927483881427     0.0405534955108
v  =      0.0008094858976    -0.0000587057170    -0.0001324604177
  
DJ =  2450100.500
x  =      0.0203404288541     0.0917903484568     0.0390680943969
v  =      0.0007964587389    -0.0001328329038    -0.0001644470244
  
================================================================================
			J.Desmars (2013/01/08)
================================================================================
[ICO]NameLast modifiedSizeDescription
[PARENTDIR]Parent Directory  -  
[TXT]PH12.htm2013-02-28 21:46 5.5K 
[TXT]README.txt2013-02-28 21:46 4.9K 
[ ]ph12.dat2013-02-28 21:49 7.2M 
[ ]ph12.tar.gz2013-02-28 21:48 2.7M 
[ ]r-ph12.f902013-02-28 21:46 1.7K 
[ ]test.f902013-02-28 21:46 691