| DATA_SET_DESCRIPTION |
Data Set Overview : This dataset provides taxonomic classifications of asteroids in each of six different systems: Tholen (1984, 1989) [THOLEN1984, THOLEN1989]; Barucci, et al. (1987) [BARUCCIETAL1987]; Tedesco, et al. (1989) [TEDESCOETAL1989]; Howell, et al. (1994) [HOWELLETAL1994], Xu et al. (1995) [XUETAL1995], and Bus and Binzel (2002) [BUS&BINZEL2002]. The data set contains entries for 1956 objects. Each of the six taxonomies represented in this data set produced classifications for a subset of these objects: Tholen (1984, 1989) 978 objects Barucci et al. (1987) 438 objects Tedesco et al. (1989) 357 objects Howell et al. (1994) 112 objects Xu et al. (1995) 221 objects Bus and Binzel (2002) 1447 objects Asteroid taxonomy is the grouping of asteroids into a small number of classes whose members have similar spectral reflectance properties. The classification efforts prior to 1990 utilized only the reflectivities between 0.3 and 1.1 microns for this purpose (see Zellner et al. 1985 and Tedesco 1989); more recently, infrared data extending to 2.5 microns were used for a new classification scheme (Howell et al. 1994). There are many different ways to perform this type of cluster analysis, and the six different classifications tabulated in this dataset represent six different algorithms developed during the past twenty years (Tholen 1984, Barucci et al. 1987, Tedesco et al. 1989, Howell et al. 1994, Xu et al. 1995, and Bus and Binzel 2002), as well as an extension of one of these algorithms to additional objects (Tholen 1989, Mueller et al. 1992). These six taxonomies have effectively replaced the older schemes used previously. Detailed descriptions of each method can be found in the corresponding references. In this particular dataset, the six parameter fields indicate which parameters were used to arrive at the classification for the corresponding asteroid in each of the six taxonomies. A number indicates the number of color indices utilized, the letter 'G' indicates that a groundbased radiometric albedo was also utilized, and the letter 'I' indicates that an IRAS radiometric albedo was utilized. The letter 'A' indicates that an albedo of unspecified source was used to eliminate some other possible classes based on the spectrum alone. The letter 'S' indicates that the classification is based on a medium resolution spectrum published by Chapman and Gaffey (1979), while the higher resolution spectra obtained by Xu et al. (1995) and Bus and Binzel (2002) are indicated by a lowercase 's'. The Howell et al. (1994) classifications are all based on a combination of 8-color (Zellner et al. 1985) and 52-color (Bell et al. 1988) data, resampled at 65 points to provide more uniform wavelength sampling. Five entries have a notation in the comment field regarding the identification of the object. The details pertaining to each case are in the column description for the comment field in the data label. References: Barucci, M. A., M. T. Capria, A. Coradini, and M. Fulchignoni 1987. Classification of asteroids using G-mode analysis. Icarus 72, 304-324. Bell, J. F., P. D. Owensby, B. R. Hawke, and M. J. Gaffey 1988. The 52-color asteroid survey: Final results and interpretation. Lunar Planet. Sci. Conf. XIX, 57. Bowell, E., T. Gehrels, and B. Zellner 1979. Magnitudes, colors, types, and adopted diameters of the asteroids. In Asteroids (T. Gehrels, Ed.), pp. 1108-1129. Univ. of Arizona Press, Tucson. Bus, S.J. and R.P. Binzel 2002. Phase II of the small main-belt asteroid spectroscopic survey: A feature-based taxonomy. Icarus 158, 146-177. Chapman, C. R., and M. J. Gaffey 1979. Reflectance spectra for 277 asteroids. In Asteroids (T. Gehrels, Ed.), pp. 655-687. Univ. of Arizona Press, Tucson. Howell, E. S., E. Merenyi, and L. A. Lebofsky 1994. Classification of asteroid spectra using a neural network. J. Geophys. Res. 99, 10847-10865. Mueller, B. E. A., D. J. Tholen, W. K. Hartmann, and D. P. Cruikshank 1992. Extraordinary colors of asteroidal object (5145) 1992 AD. Icarus 97, 150-154. Tedesco, E. F. 1989. Asteroid magnitudes, UBV colors, and IRAS albedos and diameters. In Asteroids II (R. P. Binzel, T. Gehrels, and M. S. Matthews, Eds.), pp. 1090-1138. Univ. of Arizona Press, Tucson. Tedesco, E. F., J. G. Williams, D. L. Matson, G. J. Veeder, J. C. Gradie, and L. A. Lebofsky 1989. A three-parameter asteroid taxonomy. Astron. J. 97, 580-606. Tholen, D. J. 1984. Asteroid Taxonomy from Cluster Analysis of Photometry. Ph.D. dissertation, University of Arizona. Tholen, D. J. 1989. Asteroid taxonomic classifcations. In Asteroids II (R. P. Binzel, T. Gehrels, and M. S. Matthews, Eds.), pp. 1139-1150. Univ. of Arizona Press, Tucson. Xu, S., R. P. Binzel, T. H. Burbine, S. J. Bus 1995. Small main-belt asteroid spectroscopic survey: Initial Results. Icarus 115, 1-35. Zellner, B., D. J. Tholen, and E. F. Tedesco 1985. The eight-color asteroid survey: Results for 589 minor planets. Icarus 61, 355-416. Modification History : The asteroid taxonomy data set was first reviewed and ingested in 1993, and was updated in 1997 to include the neural net taxonomy of Howell et al. (1994) [HOWELLETAL1994]. It was updated in 1999 to include the taxonomic classifications of the SMASS survey, Xu et al. (1995) [XUETAL1995]. In 2002 it was updated to include the classifications of the SMASSII survey, Bus and Binzel (2002) [BUS&BINZEL2002]. Parameters : The data table includes taxonomic classifications and the parameters used to derived the classification in each of the classification systems.
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