PDS_VERSION_ID = PDS3 /* File Characteristics */ RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 34 FILE_RECORDS = 6842 /* Data Object Pointers */ ^TABLE = "ASTERMAG.TAB" /* Identification Keywords */ DATA_SET_ID = "EAR-A-5-DDR-ASTERMAG-V3.0" PRODUCT_NAME = "Asteroid Magnitudes and Slopes" PRODUCT_ID = "ASTERMAG-ASTERMAG-199604" INSTRUMENT_HOST_NAME = "N/A" INSTRUMENT_NAME = "N/A" TARGET_NAME = ASTEROID PRODUCT_CREATION_TIME = 1996-03-29 /* Peer Review Date */ START_TIME = "N/A" STOP_TIME = "N/A" RECORD_FORMAT = "(I5,1X,F5.2,1X,F5.2,1X,A1,1X,A9,1X,A1)" /* Data Object Descriptions */ OBJECT = TABLE ROWS = 6842 ROW_BYTES = 34 INTERCHANGE_FORMAT = ASCII COLUMNS = 6 DESCRIPTION = " IAU-adopted magnitude parameters (absolute V magnitude and slope parameter) for all numbered asteroids. The absolute magnitude is variously given to 0.01, 0.1, or 1.0 mag precision, depending on the accuracy and consistency of the data used to arrive at the value. Those slope parameters that were determined by fitting the IAU-adopted phase function (see Bowell et al. 1989) to data are given an origin code letter of 'f' (for 'fitted'); all others are given a code letter of 'a' (for 'assumed'). The default value is 0.15 in all cases. Note that because most absolute magnitudes are based on apparent magnitudes measured at non-zero phase angles, the value of the absolute magnitude does depend on the assumed value for the slope parameter. A change in the assumed value of the slope parameter (based on a taxonomic classification, for example) should not be made independently of the absolute magnitude. 'MPC' in the reference field stands for 'Minor Planet Circular', published on behalf of Commission 20 of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138. This version of the dataset contains magnitude parameters for all asteroids numbered as of the 1996 February 4 batch of Minor Planet Circulars and includes 6842 entries. Although errors are known to exist, more accurate values have yet to be adopted by the IAU. In two cases, described below, the IAU-adopted values were replaced by better ones. Improved values will be incorporated into this database after they become formally adopted. The Asteroid Subnode of the Planetary Data System would be happy to accept published values of improved magnitude parameters for forwarding to the appropriate IAU committee. References: Bowell, E., B. Hapke, D. Domingue, K. Lumme, J. Peltoniemi, and A. W. Harris 1989. Application of photometric models to asteroids. In Asteroids II (R. P. Binzel, T. Gehrels, and M. S. Matthews, Eds.), pp. 524-556. Univ. of Arizona Press, Tucson. Spencer, J. R., L. A. Akimov, C. Angeli, P. Angelini, M. A. Barucci, P. Birch, C. Blanco, M. Buie, A. Caruso, V. G. Chiornij, F. Colas, P. Dentchev, M. C. De Sanctis, E. Dotto, M. Fulchignoni, S. Green, A. Harris, T. Hudecek, A. V. Kalashnikov, V. V. Kobelev, V. P. Kozhevnikov, Y. Krugly, D. Lazzaro, J. Lecacheux, J. MacConnell, T. Michalowski, R. A. Mohamed, B. Mueller, T. Nakamura, C. Neese, W. Osborn, P. Pravec, D. Riccioli, V. Shevchenko, D. Tholen, F. Velichko, C. Venditti, R. Venditti, W. Wisniewski, J. Young, and B. Zellner 1995. The lightcurve of 4179 Toutatis: Evidence for complex rotation. Icarus 117, 71-89. David J. Tholen 1995 February 20 " OBJECT = COLUMN NAME = "ASTEROID ID" DESCRIPTION = "Asteroid catalog number." DATA_TYPE = ASCII_INTEGER START_BYTE = 1 BYTES = 5 FORMAT = I5 END_OBJECT OBJECT = COLUMN NAME = "ABSOLUTE V MAGNITUDE" UNIT = "MAGNITUDE" DESCRIPTION = " The absolute magnitude is variously given to 0.01, 0.1, or 1.0 mag precision, depending on the accuracy and consistency of the data used to arrive at the value. " DATA_TYPE = ASCII_REAL START_BYTE = 7 BYTES = 5 FORMAT = "F5.2" END_OBJECT OBJECT = COLUMN NAME = "SLOPE PARAMETER" DESCRIPTION = " Those slope parameters that were determined by fitting the IAU-adopted phase function to data are given an origin code letter of 'f' (for 'fitted'); all others are given a code letter of 'a' (for 'assumed'). The default value is 0.15 in all cases. Note that because most absolute magnitudes are based on apparent magnitudes measured at non-zero phase angles, the value of the absolute magnitude does depend on the assumed value for the slope parameter. A change in the assumed value of the slope parameter (based on a taxonomic classification, for example) should not be made independently of the absolute magnitude. " DATA_TYPE = ASCII_REAL START_BYTE = 13 BYTES = 5 FORMAT = "F5.2" END_OBJECT OBJECT = COLUMN NAME = "SLOPE PARAMETER ORIGIN FLAG" DESCRIPTION = " Those slope parameters that were determined by fitting the IAU-adopted phase function to data are given an origin code letter of 'f' (for 'fitted'); all others are given a code letter of 'a' (for 'assumed'). " DATA_TYPE = CHARACTER START_BYTE = 19 BYTES = 1 FORMAT = A1 END_OBJECT OBJECT = COLUMN NAME = "REFERENCE" DESCRIPTION = " This file contains magnitude parameters for all asteroids numbered as of the 1994 January 27 batch of Minor Planet Circulars and includes 5838 entries. Although errors are known to exist, more accurate values have yet to be adopted by the IAU. In two cases, described in the notes column below, The IAU-adopted values were replaced by better ones. Improved values will be incorporated into this database after they become formally adopted. The Asteroid Subnode of the Planetary Data System would be happy to accept published values of improved magnitude parameters for forwarding to the appropriate IAU committee. " DATA_TYPE = CHARACTER START_BYTE = 21 BYTES = 9 FORMAT = A9 END_OBJECT OBJECT = COLUMN NAME = "NOTE" DESCRIPTION = " Comments on individual entries in this dataset: 1 - The absolute magnitude of 16 for (878) Mildred was adopted by the IAU prior to the recovery of this formerly lost asteroid (see MPC 17260). Following recovery, the inclusion of new and recent astrometric observations led to a significant revision of the absolute magnitude for this object (see MPC 18400). This dataset reflects this more recent value, rather than the older IAU-adopted value. 2 - The IAU-adopted absolute magnitude of 14.0 for (4179) Toutatis (see MPC 17271) was known to be seriously in error prior to this Apollo asteroid's 1992 December 08 close approach to the Earth. The values included here are from Spencer et al. (1995). " DATA_TYPE = CHARACTER START_BYTE = 31 BYTES = 1 FORMAT = A1 END_OBJECT END_OBJECT END