Method of Asteroid S/C Type Classification Using Color Indices

The color indices obtained from multi-color photometry have important significance of reference in the S/C type classification of asteroids, and the color parameter a derived from the principal component analysis of color indices is a key parameter of classification. Two methods, the direct demarcation at a = 0 and the cluster analysis of a-parameters, are applied to the asteroid S/C type classifications of the SDSSMOC4 and XSTPS-GAC (Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-Center) multi-color data samples, respectively. The results show that the two methods are effective and consistent in the case of large samples, and well consistent with the Carvano's result of S/C type classification, and that the a = 0 demarcation method is sensitive to the variation of sample space, but the method of cluster analysis is more stable.