Contents of: VII/108C/./prop_doc.txt

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EXPLANATIONS FOR ASTEROID PROPER ELEMENTS AND FAMILY ASSIGNMENTS                
                                                                                
   SUPPLIED BY                                                                  
   J. G. WILLIAMS                                                               
   JPL, 238-332                                                                 
   4800 OAK GROVE DR.                                                           
   PASADENA, CA 91109                                                           
                                                                                
   DECEMBER 2, 1987                                                             
                                                                                
THESE RESULTS ARE NEARLY THE SAME AS GIVEN IN REFERENCE 1 (1979 ASTEROID        
BOOK).  ADDITIONS HAVE BEEN MADE FOR TROJANS, HILDAS, AND OTHER ODD TYPES       
(279, 887, 944, 1362, AND 1373) SO THAT ASTEROIDS 1 THROUGH 1796 ARE            
REPRESENTED WITH SOME ENTRY INCLUDING SEMIMAJOR AXIS, THOUGH NOT WITH           
THE REMAINING PROPER ELEMENTS FOR THE ODD TYPES.  SOME PROPER ELEMENTS          
WERE REVISED, MOST IMPORTANTLY FOR LOST OBJECTS AND THOSE WHICH FORMERLY        
HAD POOR OSCULATING ELEMENTS.  THE NEW ORBITS FOR 330 AND 864 HAVE              
BEEN ADDED.  THE REVISIONS IN FORMERLY POOR ORBITS HAVE LED TO CHANGES          
IN FAMILY DESIGNATIONS FOR 561, 637, 1037, 1265, 1381, AND 1686.  THE           
ADDITIONS AND REVISIONS IN PROPER ELEMENTS ARE INDICATED WITH A 2 IN            
THE REFERENCE COLUMN.                                                           
                                                                                
PROPER ELEMENT FILE                                                             
                                                                                
THE PROPER ELEMENT FILE CONSISTS OF ENTRIES FOR THE FIRST 1796 ASTEROIDS,       
ONE LINE PER ASTEROID, WITH THE PARAMETERS SEPARATED BY SPACES. The fields 
are:  
                                                                                
   PARAMETER     DEFINITION                                                     
   NUMBER        ASTEROID NUMBER                                                
   A             PROPER SEMIMAJOR AXIS (AU)                                     
   E             PROPER ECCENTRICITY                                            
   SINI          PROPER SINE INCLINATION                                        
   WBAR          PROPER LONGITUDE OF PERIHELION (DEGREES), EQUINOX              
                 AND EPOCH OF 1950.0                                            
   ANODE         PROPER LONGITUDE OF ASCENDING NODE (DEGREES), EQUINOX          
                 AND EPOCH OF 1950.0                                            
   DWBAR         RATE (ARCSEC/YR) OF PROPER LONGITUDE OF PERIHELION             
   DNODE         RATE (ARCSEC/YR) OF PROPER LONGITUDE OF NODE                   
   RES           INDEX INDICATING A RESONANCE OR SPECIAL CASE.                  
                 VALUES 1-16 IDENTIFY A SECULAR RESONANCE NUMBER.               
                 COMMENSURABILITIES ARE INDICATED AS 1:1 FOR                    
                 TROJANS, 3:2 FOR HILDAS, ETC.  W L DENOTES AN                  
                 ARGUMENT OF PERIHELION LIBRATOR, JXR A JUPITER                 
                 CROSSER, AND SXR A SATURN CROSSER.  A BLANK VALUE              
                 INDICATES MORE NORMAL OBJECTS.                                 
   DMARS         CLOSEST COLINEAR DISTANCE OF APPROACH TO MARS (AU).            
                 A NEGATIVE VALUE INDICATES A MARS CROSSER.                     
   DJUP          CLOSEST COLINEAR DISTANCE OF APPROACH TO JUPITER (AU)          
   Q             QUALITY CODE RESERVED FOR PALOMAR-LEIDEN ASTEROIDS.            
                 VALUES 1, 2, 3, 4, X, 0 ARE IN DECREASING ORDER OF             
                 ACCURACY.  SEE PALOMAR-LEIDEN SURVEY FOR DETAILS.              
                 A BLANK, NOT A ZERO, IS USED FOR NUMBERED ASTEROIDS.           
   FAMILY        FAMILY IDENTITY IF A FAMILY MEMBER.                            
   REF           REFERENCE NUMBER IN BIBLIOGRAPHY BELOW.                        
                                                                                
WARNINGS                                                                        
                                                                                
IF THE FLAG NRES IS NONZERO, THE PROPER ELEMENTS (EXCEPT A), THE                
   RATES, AND THE DISTANCES WILL HAVE DEGRADED ACCURACY.  IN SOME               
   CASES THE RESULTS MAY BE ERRONEOUS BUT USUALLY ARE USABLE IF                 
   THE VALUES ARE PRESENT.  OCCASIONAL FAILURES OF CONVERGENCE                  
   DURING THE DMARS AND DJUP CALCULATIONS ARE INDICATED                         
   BY BLANKS FOR BOTH PARAMETERS.  A TEST FOR A ZERO VALUE OF DJUP              
   WILL ALWAYS DETECT THIS CASE.  FOR RESONANCES 5 AND 6, FAILURES              
   OF CONVERGENCE DURING THE CALCULATION OF THE PROPER ELEMENTS WERE            
   SO COMMON THAT THESE PROPER ELEMENTS (EXCEPT A) AND THE CLOSEST              
   APPROACH DISTANCES ARE BLANKED OUT.  THE NODE RATE IS INDICATED              
   IN SUCH CASES BUT MAY BE INACCURATE OR ERRONEOUS.                            
THE USER IS WARNED THAT THE PROPER ELEMENT CALCULATIONS WILL HAVE               
   DECREASED ACCURACY NEAR THE SECULAR RESONANCES AND NEAR                      
   COMMENSURABILITIES.  THE ACCURACIES FOR MARS CROSSERS WILL ALSO              
   BE DECREASED AND THE ACCURACY OF THE CALCULATIONS FOR DEEP EARTH             
   CROSSERS IS VERY POOR.                                                       
OBJECTS IN THE OUTER PORTION OF THE BELT HAVE DEGRADED ACCURACY                 
   FOR DWBAR AND POSSIBLY E.                                                    
THIS FILE CONTAINS SIX ASTEROIDS LOST AT THE TIME OF THE CALCULATIONS:          
   473, 719, 724, 878, 1026, AND 1179.  A FEW OF THE LOWER QUALITY              
   ORBITS OF REF 1 HAVE NOT BEEN UPDATED, E. G., 452.                           
                                                                                
FAMILIES                                                                        
                                                                                
NUMBERS LESS THAN 100 CORRESPOND TO FAMILIES PREVIOUSLY FOUND (HIRAYAMA,        
   BROUWER, ARNOLD, OR LINDBLAD AND SOUTHWORTH), BUT USUALLY ALTERED            
   HERE.  NUMBERS GREATER THAN 100 ARE SIGNIFICANTLY DIFFERENT.  IT             
   SHOULD BE APPRECIATED THAT THE QUALITY AND UNIQUENESS OF FAMILY              
   IDENTIFICATIONS VARIES WIDELY SINCE MANY FAMILIES ARE POORLY                 
   POPULATED, CROWDED, OR OVERLAPPING WHILE OTHERS ARE ISOLATED OR              
   WELL POPULATED.                                                              

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