CCSD3ZF0000100000001NJPL3IF0PDS200000001 = SFDU_LABEL /* File Format and Length */ RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 105 FILE_RECORDS = 385 DATA_SET_ID = "A-5-DDR-POLE_POSITION-V1.0" /* Record Pointer to Major Object */ ^TABLE = "POLE.TAB" /* Description of Object in File */ RECORD_FORMAT = "(I5,1X,A5,2X,A1,4(2X,A1,1X,I3,1X,I3),2X, F10.8,2X,A1,1X,F4.2,1X,F4.2,2X,A6,2X,A10)" OBJECT = TABLE ROWS = 385 ROW_BYTES = 105 INTERCHANGE_FORMAT = ASCII COLUMNS = 18 DESCRIPTION = " ASTEROID SPIN VECTOR DETERMINATIONS June 1993 version, supplied by Per Magnussen, Astronomiska observatoriet, Box 515, S-751 20 Uppsala, Sweden. This is a comprehensive tabulation of asteroid spin vector determinations. Supplementary information on shape models and albedo variegation is also included, but only when part of a spin vector determination. If you find omissions and errors or have suggestions for future improvements please contact me on the above address. For some asteroids a large number of independent solutions have been published. This may be confusing for those who are not interested in the spin vector determinations, but are looking for quick results that they can use for their own applications. I therefore include a 'synthesis' of our knowledge of the spin vector for some asteroids. I estimate that these synthesis results have a high reliability and an accuracy in the spin vector direction of 10 degrees or less. They were obtained by taking averages of the most recent independent results, with weights based on the method used and the amount and type of the input data. This procedure is neccessarily somewhat subjective, and can't replace a careful evaluation of the original results. This dataset is an update (June 1993) to the file of the same name that appeared in the Asteroids II database. This file contains 385 entries on 84 different asteroids. " OBJECT = COLUMN NAME = "ASTEROID_ID" DATA_TYPE = ASCII_INTEGER START_BYTE = 1 BYTES = 5 FORMAT = I5 END_OBJECT OBJECT = COLUMN NAME = "BASIC_DATA_ID" DESCRIPTION = " BASIC DATA from which pole coordinates, senses of rotation and rejection of spurious solutions are based are designated by the letters: A = Amplitudes of lightcurves D = Individual data-points of photometric lightcurves E = Epochs (e.g. times of lightcurve extrema) F = Fourier coefficients of photometric lightcurves G = Galileo spacecraft images I = Infrared pre- and post-opposition differences M = Magnitudes (usually at maximum light) O = Occultation observations P = Infrared polarimetry R = Radar observations (gives a pole constraint, rather direction) S = Speckle interferometry V = Visual position angles Z = Zero and non-zero amplitude apparitions imply pole-on view in former case " DATA_TYPE = CHARACTER START_BYTE = 7 BYTES = 5 FORMAT = A5 END_OBJECT OBJECT = COLUMN NAME = "POLE_SOLUTION_FLAG" DESCRIPTION = " The terms 'the North Pole' and 'the South Pole' are ambiguous and they are avoided in this table. Instead I use the spin angular velocity direction as defined by the 'right-hand-rule'. With the spin vector given in this way we also avoid the ambiguous terms 'prograde rotation' and 'retrograde rotation'. The exception is determinations of the sense of rotation only (no spin axis given), for which the published designations prograde and retrograde are repeated faithfully in the present table. The original authors usually don't specify if they base the prograde/retrograde distinction on the ecliptic plane, the asteroid's orbital plane, or something else (the truth usually depends in a complicated way on the distribution of observing geometries). Thus, the present table simply preserves the orginal fuzziness of the prograde/retrograde terms. The pole solution flag takes the following values: P - prograde R - retrograde N - a note on the pole solution occurs in the 'note' column. The direction of the spin vectors (defined by the 'right-hand-rule') are given in degrees in the ecliptic system of equinox 1950. Up to four multiple solutions are given on the same line. For rejected solutions a letter specifying the data primarily responsible for the rejection appears in the associated flag column. The interpretation of the four solution columns and the rejections requires some knowledge of the symmetry properties of spin vector determinations. Methods based on aspect dependences (e.g. amplitude and magnitude methods) tend to give two spin axis solutions for main-belt asteroid with moderate orbital inclination (due to the near symmetry of the observational geometries in the ecliptic plane). Corresponding to each spin axis solution we have two spin vector directions. Many papers refer to results as 'pole solutions' without further explanations. Whenever the method used does not contain information on the sense of rotation, I interpret these as spin axis determinations and represent each one by two opposite spin vector directions. Thus for many asteroids the solutions for the spin vector directions cluster in four well-defined groups, which correspond to the four columns of spin vector directions in the table. A result which demonstrates (explicitly or implicitly) that one of the four solutions can be rejected is indicated by a letter in the flag accompanying the appropriate solution. The letter indicates the type of data primary responsible for the rejection. The above four-fold clustering of symmetric solutions is not applicable to certain objects. The distinction between the four groups may break down for objects in high inclination orbits (e.g. 2 Pallas), for objects with spin axes close to the ecliptic plane, and for objects whose lightcurves are difficult to interpret (e.g. 532 Herculina). For Earth-approaching objects it often reduces to a two fold clustering. In these cases a rejection flag is used only if the meaning is clear from the context. " DATA_TYPE = CHARACTER START_BYTE = 14 BYTES = 1 FORMAT = A1 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_ONE_POLE_FLAG" DESCRIPTION = " A letter in this column specifies that the solution indicated has been rejected. (A blank in this column means the solution has not been rejected.) The letter specifies which data (as coded below) are primarily responsible for the rejection. E = Epochs (e.g. times of lightcurve extrema) F = Fourier coefficients of photometric lightcurves O = Occultation observations P = Infrared polarimetry S = Speckle interferometry V = Visual position angles X = No specific reason given for rejection " DATA_TYPE = CHARACTER START_BYTE = 17 BYTES = 1 FORMAT = A1 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_ONE_POLE_COORD_LATITUDE" UNIT = DEGREE DATA_TYPE = ASCII_INTEGER START_BYTE = 19 BYTES = 3 FORMAT = I3 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_ONE_POLE_COORD_LONGITUDE" UNIT = DEGREE DATA_TYPE = ASCII_INTEGER START_BYTE = 23 BYTES = 3 FORMAT = I3 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_TWO_POLE_FLAG" DESCRIPTION = " A letter in this column specifies that the solution indicated has been rejected. (A blank in this column means the solution has not been rejected.) The letter specifies which data (as coded below) are primarily responsible for the rejection. E = Epochs (e.g. times of lightcurve extrema) F = Fourier coefficients of photometric lightcurves O = Occultation observations P = Infrared polarimetry S = Speckle interferometry V = Visual position angles X = No specific reason given for rejection " DATA_TYPE = CHARACTER START_BYTE = 28 BYTES = 1 FORMAT = A1 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_TWO_POLE_COORD_LATITUDE" UNIT = DEGREE DATA_TYPE = ASCII_INTEGER START_BYTE = 30 BYTES = 3 FORMAT = I3 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_TWO_POLE_COORD_LONGITUDE" UNIT = DEGREE DATA_TYPE = ASCII_INTEGER START_BYTE = 34 BYTES = 3 FORMAT = I3 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_THREE_FLAG" DESCRIPTION = " A letter in this column specifies that the solution indicated has been rejected. (A blank in this column means the solution has not been rejected.) The letter specifies which data (as coded below) are primarily responsible for the rejection. E = Epochs (e.g. times of lightcurve extrema) F = Fourier coefficients of photometric lightcurves O = Occultation observations P = Infrared polarimetry S = Speckle interferometry V = Visual position angles X = No specific reason given for rejection " DATA_TYPE = CHARACTER START_BYTE = 39 BYTES = 1 FORMAT = A1 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_THREE_POLE_COORD_LATITUDE" UNIT = DEGREE DATA_TYPE = ASCII_INTEGER START_BYTE = 41 BYTES = 3 FORMAT = I3 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_THREE_POLE_COORD_LONGITUDE" UNIT = DEGREE DATA_TYPE = ASCII_INTEGER START_BYTE = 45 BYTES = 3 FORMAT = I3 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_FOUR_FLAG" DESCRIPTION = " A letter in this column specifies that the solution indicated has been rejected. (A blank in this column means the solution has not been rejected.) The letter specifies which data (as coded below) are primarily responsible for the rejection. E = Epochs (e.g. times of lightcurve extrema) F = Fourier coefficients of photometric lightcurves O = Occultation observations P = Infrared polarimetry S = Speckle interferometry V = Visual position angles X = No specific reason given for rejection " DATA_TYPE = CHARACTER START_BYTE = 50 BYTES = 1 FORMAT = A1 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_FOUR_POLE_COORD_LATITUDE" UNIT = DEGREE DATA_TYPE = ASCII_INTEGER START_BYTE = 52 BYTES = 3 FORMAT = I3 END_OBJECT OBJECT = COLUMN NAME = "SOLUTION_FOUR_POLE_COORD_LONGITUDE" UNIT = DEGREE DATA_TYPE = ASCII_INTEGER START_BYTE = 56 BYTES = 3 FORMAT = I3 END_OBJECT OBJECT = COLUMN NAME = "SIDEREAL_PERIOD" DESCRIPTION = " Only periods accurate enough to bridge inter-apparitional gaps and produce absolute rotational phases for the whole data set are included. Less accurate synodic period determinations exist for many more objects. As evident in the table, the agreement between sidereal period determinations tend to be either very good or very bad. This is due to the non-uniform time-distribution of the observations, which tend to give many local chi-square minima. " UNIT = DAY DATA_TYPE = ASCII_REAL START_BYTE = 61 BYTES = 10 FORMAT = "F10.8" END_OBJECT OBJECT = COLUMN NAME = "SHAPE_MODEL_FLAG" DESCRIPTION = " This flag can take the following values: A - An albedo model was used. Refer to comment in note column. N - Refer to comment in note field. " DATA_TYPE = CHARACTER START_BYTE = 73 BYTES = 1 FORMAT = A1 END_OBJECT OBJECT = COLUMN NAME = "A_OVER_B_MODEL" DESCRIPTION = " MODEL. Many pole determination methods are based on a tri-axial ellipsoid model with semi-axes a > b > c which rotates about the c-axis. Corrections for non-geometric scattering and albedo variegation have often not been made. A warning must therefore be made against direct identification of the model axis-ratios with the asteroid shape. When a non-ellipsoidal model is used, the model is described in a note in the note column. The table is not a comprehensive list of asteroid shapes and albedo models, but includes models obtained as by-products of pole determinations. " DATA_TYPE = ASCII_REAL START_BYTE = 75 BYTES = 4 FORMAT = "F4.2" END_OBJECT OBJECT = COLUMN NAME = "B_OVER_C_MODEL" DESCRIPTION = " MODEL. Many pole determination methods are based on a tri-axial ellipsoid model with semi-axes a > b > c which rotates about the c-axis. Corrections for non-geometric scattering and albedo variegation have often not been made. A warning must therefore be made against direct identification of the model axis-ratios with the asteroid shape. When a non_ellipsoidal model is used, it is described in a note in the note column. The table is not a comprehensive list of asteroid shapes and albedo models, but includes models obtained as by-products of pole determinations. " DATA_TYPE = ASCII_REAL START_BYTE = 80 BYTES = 4 FORMAT = "F4.2" END_OBJECT OBJECT = COLUMN NAME = "REFERENCE_ID" DESCRIPTION = " The reference codes are formed by 2-3 letters of the first author name, followed by '+' if there are more authors, and the last two digits of the publication year. Full expansions of the codes are given in the reference list, which may be found in the POLE_REF.TAB table (PDS dataset A-5-DDR-POLE_POSITION_REF-V1.0). " DATA_TYPE = CHARACTER START_BYTE = 86 BYTES = 6 FORMAT = A6 END_OBJECT OBJECT = COLUMN NAME = NOTE DESCRIPTION = " The numbers in this column refer to the following notes. For further information, see the individual references. 1. Solution curve 2. Value given for a/b is lower limit. 3. Different spin axis solutions for different apparitions was interpreted as indicating a precessing motion. 4. Symmetric solution obtained, but quantitative specification is missing. 5. Consistency check of previous spin vector determinations. 6. Based on a radar experiment giving constraints on the aspect angle at the time of observation. 7. Based on two radar experiments giving an aspect circle at the time of observation. 8. Modelled as a cylinder with hemispherical ends. 9. Modelled as a cylinder cut out of a sphere. 10. Complex shape. 11. Modelled as a Jacobi ellipsoid. 12. Modelled as 8 octants of ellipsoids put together to form a continuous surface. 13. Modelled as an ellipsoid with a piece removed by a plane cut. 14. Modelled as an irregular polyhedron. 15. Modelled as a sphere with free albedo facets. 16. Results show that there are no significant albedo variations. 17. Modelled using a sherical harmonics expansion of the shape. 18. Albedo model with a single big spot. 19. Modelled as a sphere with two dark regions. 20. Speckle images show albedo variations. 21. Bi-axial ellipsoid (a/b = 1.15) with a flat region just off the South Pole. 22. Also presented in Ful+91. 23. Also presented in English in Lup+90. 24. Also presented in Mi+90c. 25. a/b is assumed value. 26. b/c is assumed value. 27. a/b is a mean value of two significantly different solutions. 28. b/c is a mean value of two significantly different solutions. 29. Sidereal period is a mean value of two significantly different solutions. " DATA_TYPE = CHARACTER START_BYTE = 94 BYTES = 10 FORMAT = A10 END_OBJECT END_OBJECT = TABLE OBJECT = DSREFINFO REFERENCE_KEY_ID = "MAGNUSSEN1989" OBJECT = REFERENCE DOCUMENT_TOPIC_TYPE = "ASTEROID POLE POSITIONS" JOURNAL_NAME = "N/A" PUBLICATION_DATE = 1989 REFERENCE_DESC = "Magnussen, P. 1989. Pole Determinations of Asteroids. In 'Asteroids II', (T. Gehrels, Ed.), pp. 1180-1190. University of Arizona Press, Tucson." OBJECT = REFERENCE_AUTHORS AUTHOR_FULL_NAME = "PER MAGNUSSEN" END_OBJECT = REFERENCE_AUTHORS END_OBJECT = REFERENCE END_OBJECT = DSREFINFO END