Results of the Seven-Color Asteroid Survey: Infrared Spectral Observations of ∼50-km Size S-, K-, and M-Type Asteroids

We present the results of a spectral survey of S-, K-, Q-, and M-type asteroids in seven colors in the infrared (0.9 to 2.3 μm) conducted at the Infrared Telescope Facility on Mauna Kea from 1992-1994. This asteroid spectral collection consists of a total of 126 observed objects. Among them are 96 S-types, 17 M-types, 1 Q-type, 1 C-type, 4 previously reported K-types, and possibly 7 newly identified K-types. The average size of seven-color asteroid survey (SCAS) objects is about 50 km in diameter, compared to the average size of 100 km for the 52-color survey S-types (Bell, J. F., B. R. Hawke, P. D. Owensby, and M. J. Gaffey 1988. The 52-color asteroid survey: Final results and interpretations. Lunar Planet. Sci. Conf. XIX, 57-58). The salient aspects of analyses of these data are presented in four parts: (1) The mineralogic diagnostic information represented by the seven colors, (2) the search for an ordinary chondrite-like parent body among the smaller S-types, (3) the discovery of new K-type objects among the Tholen classified S-types, and (4) the continuum slope range of M-type asteroids.