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PROPER.DOC
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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
PHONE: COMMERCIAL 818 354-6466, FTS 792-6466
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. IT MAY
BE READ AS FOLLOWS
READ( 5, N ) NUMBER, A, E, SINI, WBAR, ANODE, DWBAR, DNODE, RES,
DMARS, DJUP, Q, FAMILY, REF
N FORMAT( I4, 1X, F6.3, 2F5.3, 3F6.1, F7.1, 1X, A3, 2F6.3, 1X, A1, 1X,
A3, A2 )
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.
REFERENCES
REF 1 WILLIAMS, J. G., PROPER ORBITAL ELEMENTS AND FAMILY MEMBERSHIPS
OF THE ASTEROIDS, IN ASTEROIDS, ED. T. GEHRELS, UNIV. OF ARIZONA
PRESS, 1040-1063, 1979.
REF 2 WILLIAMS, J. G. UNPUBLISHED NUMBERED ADDITIONS AND REVISIONS.
REF 3 WILLIAMS, J. G. AND J. E. HIERATH, PALOMAR-LEIDEN MINOR PLANETS:
PROPER ELEMENTS, FREQUENCY DISTRIBUTIONS, BELT BOUNDARIES, AND
FAMILY MEMBERSHIPS, ICARUS 72, 276-303, 1987.