The problem of S-asteroid matter

Correlations are found between the position of the Fe(2+) absorption band center near 505 nm, or lambda(1) in asteroid spectra and the color index u - x (ECAS catalog system) and also between lambda(1) and relative absorption in the 355-400 nm spectral range (TRIAD data). Pyroxenes dominating compositions for E-, V-, and S-asteroid types are evaluated. It is shown that the spectral differences of light stony meteorites and those of the S-asteroid type are caused by systematic differences in their surface matter composition.